Camera, camera system and lens apparatus

ABSTRACT

A camera on which a lens apparatus is mounted is disclosed. The camera includes a controller which performs a focusing control corresponding to the mounted lens apparatus; a display unit which performs display process corresponding to an output of the controller; and a storage section which stores correction information for correcting a calculation result in the focusing control by the controller, in association with the mounted lens apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera system having the function ofautomatically adjusting parameters relating to image taking, and to acamera used for the camera system, an accessory used for the camerasystem and a lens apparatus used for the camera system.

2. Description of Related Art

Conventionally, a focus detection method based on TTL phase-differencedetection has been generally used in lens exchangeable single-lensreflex camera systems. However, it is difficult to completely match afocus position detected by this phase difference detection to the actualsurface to be focused.

This is due to factors such as errors occurring at the time of mountinga sensor module employing phase difference detection on a camera body,errors on the side of a camera body such as the dimensional errors of anoptical system constituting the sensor module, and manufacturing errorsin an image-taking lens manufactured separately from the camera body.

As a method for correcting manufacturing errors, Japanese PatentApplication Laid-Open No. 2000-292684 discloses a method for correctingerrors on the side of the camera body. This method uses a first focusdetection unit employing phase difference detection and a second focusdetection unit for autofocusing by evaluating the contrast from an imagesignal of the image-pickup element, calculates a relative displacementamount from autofocus data obtained by the first and second focusdetection units, and corrects the autofocus data of the first focusdetection unit.

In the case of single-lens reflex camera systems, several types of lensapparatuses can be mounted. Naturally, each lens apparatus has adifferent amount of manufacturing errors, resulting in the problem offocus position displacement of the image-taking lens.

One method for solving this problem is performing focus correction foreach lens apparatus. More specifically, after performing image-takingwith the focus position displaced slightly backward and forward from thefocus position set at the time of manufacturing, the obtained imagewhich best matches with a target focus position set by the user isselected, and the focus position is corrected using the relativedisplacement amount as an AF correction value.

However, the above-described conventional camera system has thefollowing problems. In the case of the camera system disclosed inJapanese Patent Application Laid Open No. 2000-292684, the displacementof the focus position caused by manufacturing errors can be correctedfor a combination of a single type of lens apparatus and a camera.However, in the case of a single-lens reflex camera, on which aplurality of lens apparatuses can be mounted, the correction is notperformed when the lens apparatus is changed, resulting in the problemof focus position displacement. Japanese Patent Application Laid OpenNo. 2000-292684 does not disclose any measures against this problem.

On the other hand, this problem can be solved in the above-describedmethod in which focus correction is performed for each lens apparatus.However, when the user has several cameras and lens apparatuses, theuser may perform image-taking not knowing whether the displacementamount of the focusing surface is corrected in the combination of cameraand lens apparatus used during the image-taking, resulting in theproblem that focusing has not been established.

Furthermore, if focus displacement is confirmed after performingimage-taking, this also results in the problem that the user cannotdetermine the camera system requires focus position adjustment orwhether there is a defect.

On the other hand, Japanese Patent Publication No. H7(1995)-117677discloses a technique for storing in advance adjustment values forperforming predetermined operations for various functions such as anautofocus adjustment function and an auto exposure function. Morespecifically, Japanese Patent Publication No. H7-117677 discloses amethod of incorporating an adjustment program for an auto exposurefunction in a camera, causing the camera to detect individualdifferences among products when a calibration signal indicating that thecamera is in a calibration step is supplied, to write an adjustmentvalue corresponding to the individual operation characteristics in anonvolatile memory, and to execute an adjustment operation.

This method is aimed at detecting, in a calibration step, individualdifferences among products resulting from discrepancies and the like ofthe components during manufacturing, storing adjustment valuescorresponding to the operation characteristics of each product at thetime of factory shipment, and performing an appropriate operation duringimage-taking, based on the adjustment data.

Additionally, Japanese Patent Application Laid-Open No. 2001-174690discloses a camera which allows the user to freely correct an adjustmentvalue set in a calibration step at the time of factory shipment and tofreely restore the setting made at the time of factory shipment, byusing a first storage section which stores an adjustment value set in acalibration step, a second storage section which stores a correctionvalue for correcting the adjustment value stored in the first storagesection and a modification section which modifies the correction valuestored in the second storage section according to the user's intention.

However, in the autofocus adjustment of a lens exchangeable camera, towhich a plurality of lens apparatuses having different functions areselectively mounted, the same correction is performed for all the lensapparatuses mounted on the camera. For example, in the case where aplurality of lens apparatuses of the same type are mounted on thecamera, the same correction is performed for all the lens apparatuses.

This method can solve the problem when the discrepancies of all themounted lens apparatuses are sufficiently small and the camera requirescalibration. On the other hand, when the lens apparatuses mountedrequire calibration, calibration has conventionally been performed forthe lens apparatuses.

When the discrepancy of both the camera and the lens apparatuses aresufficiently small, it is not necessary to perform calibration for ageneral practical use in the above-described conventional technique.However, higher focusing accuracy is required for taking special purposephotographs, such as commercial photographs, which need to be enlargedto very large sizes. To perform such a fine-tuning, it is also necessaryto take into account discrepancies which occur only when a specificcamera and a specific lens apparatus are combined.

That is, for example, even lens apparatuses of the same type havedifferent setting angles with respect to a mount disposed in front ofthe camera, so that it is necessary to eliminate such minutediscrepancies resulting from difference in the setting angle, in orderto achieve higher focusing accuracy.

SUMMARY OF THE INVENTION

The present invention has been achieved in view of these circumstances,and it is an object of the present invention to provide a camera whichallows the user to readily determine whether the focus position has beenproperly adjusted in a case where an image is observed at the time of,or after image-taking.

The present invention has been achieved in view of these problems, andit is an object of the present invention to provide a camera which canreadily obtain an accurately focused image even when a lens apparatus ischanged.

According to one aspect, the present invention provides a camera onwhich a lens apparatus is mounted, comprises a controller which performsa focusing control corresponding to the mounted lens apparatus; adisplay unit which performs display process corresponding to an outputof the controller; and a storage section which stores correctioninformation for correcting a calculation result in the focusing controlby the controller, in association with the mounted lens apparatus. Here,the controller identifies the mounted lens apparatus, determines whetherthe correction information corresponding to the identified lensapparatus is stored in the storage section, and outputs a signalcorresponding to a result of the determination to the display unit.

According to one aspect, the present invention provides a camera onwhich a plurality of lens apparatuses capable of focusing control can beselectively mounted. The camera comprises a focus detection sectionwhich obtains first information used for the focusing control, using alight flux from the mounted lens apparatus; a storage section whichstores second information for correcting the first information; and acorrection section which corrects the first information based on thesecond information. Here, the second information is informationassociated with individual information assigned to each lens apparatusmounted on the camera.

According to one aspect, the present invention provides a camera onwhich a plurality of lens apparatuses are selectively mounted. Thecamera comprises an image-pickup element which photoelectricallyconverts an object image formed by an image-taking optical system in themounted lens apparatus; an image-taking process section which performsan image-taking process of an image, using the image-pickup element; adetection section which detects a defocus amount of the image-takingoptical system; a controller which sequentially changes the defocusamount and instructs the image-taking process section to perform theimage-taking process of a plurality of images which differ in thedefocus amount; a determination section which determines the defocusamount corresponding to a specific image included in the plurality ofimages; and a storage section which stores identification information ofthe lens apparatus in association with the defocus amount determinedwith the determination section. Here, the controller performs a focusingcontrol in the image-taking optical system, using the defocus amountcorresponding to the lens apparatus mounted on the camera, determinesidentification information of the lens apparatus mounted on the camera,and controls the image-taking process for obtaining the plurality ofimages in accordance with a result of the determination.

These and further objects and features of present invention will becomeapparent from the following detailed description of preferredembodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top plan view of a digital camera according to Embodiment1 of the present invention.

FIG. 2 shows a rear view of the digital camera according to Embodiment 1of the present invention.

FIG. 3 shows a detailed view of an external liquid crystal display unitmounted on the digital camera according to Embodiment 1 of the presentinvention.

FIGS. 4A and 4B show detailed views of an internal liquid crystaldisplay unit mounted on the digital camera according to Embodiment 1 ofthe present invention.

FIG. 5 is a block diagram of the digital camera according to Embodiment1 of the present invention.

FIG. 6 is a flowchart for displaying an identification mark on thedigital camera according to Embodiment 1 of the present invention.

FIGS. 7A to 7D are diagrams showing how an identification mark isdisplayed on the digital camera according to Embodiment 1 of the presentinvention.

FIG. 8 is a flowchart for displaying an identification mark on thedigital camera according to Embodiment 1 of the present invention.

FIG. 9 is a flowchart showing a focus detection area selection sequenceof the digital camera according to Embodiment 1 of the presentinvention.

FIGS. 10A and 10B are diagrams showing how a focus detection area isselected in the digital camera according to Embodiment 1 of the presentinvention.

FIGS. 11A and 11B are flowcharts showing an image-taking sequence of thedigital camera according to Embodiment 1 of the present invention.

FIGS. 12A and 12B are diagrams showing how an identification mark isdisplayed in a reproduced image on the digital camera according toEmbodiment 1 of the present invention.

FIG. 13 is a functional block diagram of a camera system according toEmbodiment 5 of the present invention.

FIG. 14 is a flowchart showing the procedure of correcting a defocusamount of the camera system according to Embodiment 5 of the presentinvention.

FIG. 15 is a functional block diagram of a camera system according toEmbodiment 6 of the present invention.

FIG. 16 is a flowchart showing the procedure of correcting a defocusamount of the camera system according to Embodiment 6 of the presentinvention.

FIG. 17 is a block diagram showing the structure of a camera systemaccording to Embodiment 7 of the present invention.

FIG. 18 is a diagram showing an image-taking field.

FIGS. 19A to 19C are diagrams showing the interval between two images ona line sensor in the focused state and in defocused states.

FIG. 20 is a diagram showing the interval between two images in a modelwhich corresponds to an AF sensor module optical system from which acondenser lens has been omitted.

FIG. 21 is a flowchart showing the procedure of a focus detection areaselection process executed with a system controller of an electroniccamera.

FIG. 22 is a flowchart showing the procedure of a photometry areaselection process executed with the system controller of the electroniccamera.

FIG. 23 is a flowchart showing the procedure of a setting process of animage-taking mode and an AF calibration mode executed with the systemcontroller of the electronic camera.

FIG. 24 is a flowchart showing the procedure of a setting process of animage-taking mode and an AF calibration mode executed with the systemcontroller of the electronic camera.

FIG. 25 is a flowchart showing the procedure of AF calibrationimage-taking process executed with the system controller of theelectronic camera.

FIG. 26 is a flowchart showing the procedure of AF calibrationimage-taking process executed with the system controller of theelectronic camera.

FIG. 27 is a flowchart showing the procedure of an image selectionprocess in an AF calibration which is executed with the systemcontroller of the electronic camera.

FIG. 28 is a flowchart showing the procedure of an image selectionprocess in an AF calibration executed with the system controller of theelectronic camera.

FIG. 29 is a flowchart showing the procedure of a regular image-takingprocess executed with the system controller of the electronic camera.

FIG. 30 is a flowchart showing the procedure of a regular image-takingprocess executed with the system controller of the electronic camera.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIGS. 1 and 2 show a single-lens reflex type digital camera systemaccording to Embodiment 1 of the present invention.

FIG. 1 shows a top view showing the structure of the single-lens reflextype digital camera system according to Embodiment 1, and FIG. 2 shows arear view showing the structure of the digital camera system.

In FIGS. 1 and 2, reference numeral 200 denotes a camera body, and 100denotes a lens apparatus. Reference numeral 206 denotes an eyepiece forviewing an object image though an optical viewfinder. Numeral 2 denotesan AF correction confirmation button, 3 denotes an AE (auto exposure)lock button, and 228 denotes a focus detection area selection button.Reference numeral 5 denotes a vertical position AE (auto exposure) lockbutton used when the camera body 200 is held in a vertical position, andhaving the same function as the AE lock button 3. Similarly, referencenumeral 6 denotes a vertical position focus detection area selectionbutton used when the camera body 200 is held in a vertical position, andhaving the same function as the focus detection area selection button228.

Reference numeral 7 denotes a release button for performing animage-taking operation, and having a structure in which a release SW1(231) is turned ON by a first stroke operation, and a release SW2 (230)is turned ON by a second stroke operation.

Reference numeral 226 denotes a main electronic dial whose rotatingdirection and number of rotation clicks are detected by sending to thesystem controller 223, 2-bit signals which are out of phase with oneanother by, for example, 90°. By detecting the rotating direction andthe number of rotation clicks, it is possible to input numerical valuesto the camera or to switch the image-taking mode by using the mainelectronic dial in combination with other operation buttons.

It should be noted that this information setting can be carried out by,for example, the method disclosed in Japanese Patent ApplicationLaid-Open No. S60(1985)-103331.

In FIGS. 1 and 2, reference numeral 229 denotes an image-taking modeselection button, 233 denotes an AF mode selection button, and 235denotes a photometry mode selection button, which also serves as amodulation light correction button.

For example, when the main electronic dial 226 is rotated while pressingthe image-taking mode selection button 229, the mode is changed in thefollowing order: Tv priority, Av priority, manual, program, Tv priority,Av priority, manual, program . . . . Thus, the photographer can set adesired mode.

When the main electronic dial 226 is reversely rotated, the mode ischanged in the following order: program, manual, Av priority, Tvpriority, program . . . .

Further, when the Tv priority mode is set with the image-taking modeselection button 229 and the main electronic dial 226, the photographercan set a desired Tv value by rotating the main electronic dial 226.

When the Av priority mode is set with the image-taking mode selectionbutton 229 and the main electronic dial 226, the photographer can set adesired Av value by rotating the main electronic dial 226.

By rotating the main electronic dial 226 while pressing the AF modeselection button 233, the AF (autofocus) mode and the MF (manual focus)mode can be selected.

Reference numeral 250 denotes an external liquid crystal display unitequipped with an external display function which indicates image-takingconditions and the like. The details of the displayed contents will bedescribed later with reference to FIG. 3.

Reference numeral 13 denotes a display panel illumination button forturning a backlight illumination unit (not shown) disposed on the rearside of the external liquid crystal display unit 250 on or off.

Reference numeral 14 denotes an exposure compensation button forperforming exposure compensation. When the manual mode is set with theimage-taking mode selection button 229 and the main electronic dial 226,the aperture value is set by pressing the exposure compensation button14, and thereafter rotating the main electronic dial 226. In the programmode (P), the shutter priority mode (Tv) and the aperture priority mode(Av), the exposure compensation amount for changing the controlledexposure amount of the camera with respect to the measured correctexposure is set by pressing the exposure compensation button 14, andthereafter rotating the main electronic dial 226.

In FIG. 2, reference numeral 15 denotes an eyepiece shutter lever foractuating an eyepiece shutter (not shown). Rotating the eyepiece shutterlever 15 clockwise allows the eyepiece shutter (not shown) to cover theeyepiece 206, thus preventing light from entering from the eyepiece.

Reference numeral 16 denotes a dioptric correction dial for dioptricadjustment. Rotating the dioptric correction dial 16 permits a dioptricadjustment lens (not shown) to be driven, thus performing dioptricadjustment.

Reference numeral 17 denotes a sub electronic dial having a functionsimilar to that of the main electronic dial 226. When the manual mode isset with the image-taking mode selection button 229 and the mainelectronic dial 226, the sub electronic dial 17 is used to set theaperture value, and in the program mode (P), the shutter priority mode(Tv) and the aperture priority mode (Av), to set the exposurecompensation amount for changing the controlled exposure amount of thecamera with respect to the measured correct exposure.

Reference numeral 18 denotes a dial lock switch for locking the inputfunction performed with the sub electronic dial 17, and 19 denotes amain switch for disabling all the operations of the digital camera ofthis embodiment.

Reference numeral 213 denotes an LCD monitor unit (liquid crystaldisplay) which displays an obtained image or the setting conditions ofthe digital camera of this embodiment.

It should be noted that the LCD monitor unit 213 of this embodiment isof the transmissive type, so that an image cannot be visually recognizedonly by driving the LCD monitor unit and it is essential to provide abacklight illumination unit (not shown) on the rear side of the LCDmonitor unit.

Reference numeral 22 denotes a menu button for selecting various modesat the time of initializing the camera. To select a mode, a desired menuis selected by rotating the sub electronic dial 17 while pressing themenu button 22. After selecting the desired menu, the selection iscompleted by releasing the menu button 22.

Thereafter, to turn the function of the selected menu on or off, <ON> or<OFF> is selected by rotating the sub electronic dial 17 while pushing aselect button 23, and the selection is completed by releasing the selectbutton 23.

Reference numeral 24 denotes a display button for displaying, on the LCDmonitor unit 213, image files (obtained images) recorded in a recordingmedium 218. By rotating the sub electronic dial 17 while pressing thedisplay button 24, the image files are successively displayed on the LCDmonitor unit 213. After selecting a desired image, the selection iscompleted by releasing the display button 24, and the selected image isdisplayed on the LCD monitor unit 213.

Reference numeral 25 denotes an erase button for erasing image files(obtained images) recorded in the recording medium 218. After selectingan image with the display button 24 and the sub electronic dial 17, theselected image can be erased by pressing the erase button 25.

Reference numeral 26 denotes a recording image quality selection buttonfor selecting the compression ratio, the size and the like of obtainedimage files. After selecting an image quality modification menu with themenu button 22 and the sub electronic dial 17, a desired compressionratio or desired image size is selected with the recording image qualityselection button 26 and the sub electronic dial 17, and the selection iscompleted by releasing the recording image quality selection button 26.

Reference numeral 27 denotes a white balance selection button forselecting a white balance adjustment value already stored in the camera.After selecting a white balance modification menu with the menu button22 and the sub electronic dial 17, a desired white balance adjustmentvalue is selected with the white balance selection button 27 and the subelectronic dial 17, and the selection is completed by releasing thewhite balance selection button 27.

Reference numeral 28 denotes a card slot cover release knob. Rotatingthe card slot cover release knob 28 anticlockwise releases a card slotcover 29, making it possible to house or remove a recording medium withrespect to the card slot.

Reference numeral 30 denotes an access lamp, which blinks when therecording medium is accessed, for example, when an obtained image fileis written in the inserted recording medium or when an image filewritten in the recording medium is read out.

Reference numeral 218 denotes a recording medium disposed in a gripsection 36 of the digital camera of this embodiment. Reference numeral33 denotes a card eject button for removing the recording medium 218.Numeral 35 denotes a power supply battery for driving the digital camerasystem of this embodiment.

In the following, the contents displayed on the external liquid crystaldisplay unit 250 are described in detail with reference to FIG. 3. InFIG. 3, section 250 a indicates an image-taking mode status. Section 250b indicates an aperture value by seven segment display at the time ofregular image-taking, and it may also indicate the AF focus correctionamount. The timing of displaying the AF focus correction amount will bedescribed later.

Section 250 c indicates the shutter speed by seven segment display.Section 250 d indicates the remaining number of images which can betaken, and 250 h indicates a correction amount identification mark fornotifying the photographer that the AF focus correction amount has beencalculated for the combination of the camera body and the lensapparatus. The timing of displaying the AF focus correction amount andthe correction amount identification mark will be described later.

Section 250 e indicates an AF mode status, and 250 f indicates a drivemode status. Section 250 g indicates an exposure compensation amountwith dots, wherein a single dot represents ⅓ step. Section 250 jindicates the estimated remaining capacity of the power source battery35, and 250k indicates a photometry mode status.

FIGS. 4A and 4B are diagrams showing a viewfinder field in a state inwhich all the contents to be displayed in the viewfinder of the digitalcamera of this embodiment are displayed. FIG. 4A shows an overall viewof the viewfinder field, and FIG. 4B shows a detailed view of aninternal liquid crystal display unit 251 disposed outside the viewfinderfield.

In FIG. 4, reference numeral 48 denotes a visual field mask, 49 denotesa focus detection visual field frame formed on a focusing screen (notshown) for showing a focus detection area. In the focus detection visualfield frame, focus detection area segments (also referred to as “focusdetection areas”) 50 to 94 are superimposed. The structure for thesuperimposed display is disclosed, for example, in Japanese PatentApplication Laid-Open No. 2000-250120.

Reference numeral 251 denotes an internal liquid crystal display unitdisposed outside the viewfinder visual field. In FIG. 4B, section 251 aindicates the photometry mode status, and section 251 b indicates afocusing mark which is turned on at in-focus. Section 251 c indicatesthe shutter speed by seven segment display.

Section 251 d indicates the remaining number of images which can betaken, and 251 e indicates a correction amount identification mark fornotifying the photographer that the AF focus correction amount has beencalculated for the combination of the camera and the lens apparatus. Thetiming of displaying the AF focus correction amount and the correctionamount identification mark will be described later.

Section 251 f indicates the aperture value by seven segment display atthe time of regular image-taking, and it may also display the AF focuscorrection amount. The timing of displaying the AF focus correctionamount will be described later.

FIG. 5 is a block diagram showing the electrical configurationincorporated in the digital camera having the above-described structure.In FIG. 5, components that are the same as the components shown in FIGS.1 to 4 are given the same reference numerals.

As shown in FIG. 5, the lens apparatus 100 is removably mounted on thecamera body 200 according to this embodiment via a mounting section (notshown). A group of electrical contacts 107 is provided at the mountingsection.

The contact group 107 has the functions of transmitting and receivingcontrol signals, status signals, data signals and the like between thecamera body 200 and the lens apparatus 100, while supplying current atvarious voltages. It also has the function of sending a signal to asystem controller 223 upon connection of the lens apparatus.

This makes it possible to carry out communication between the digitalcamera 200 and the lens apparatus 100, thus driving an image-taking lens101 and an aperture stop 102 in the lens apparatus 100. The contactgroup 107 may also be configured so as to perform optical communication,audio communication and the like, in addition to electricalcommunication.

Additionally, although the lens apparatus of this embodiment is shown tobe constituted by a single image-taking lens for the sake ofconvenience, the actual lens apparatus is constituted by many lenses asis generally known.

An image-taking light flux from an object (not shown) is guided to aquick-return mirror 202 via the image-taking lens 101 and the aperturestop 102. The central part of the quick-return mirror 202 is formed as ahalf mirror, through which a portion of the light flux is transmittedwhen the quick-return mirror 202 has been moved down. Then, thetransmitted light flux is reflected downward by a sub mirror 203disposed on the quick-return mirror 202.

Reference numeral 204 denotes an AF sensor unit using conventional phasedifference detection which is made up of a field lens disposed in thevicinity of an image-forming surface, a reflection mirror, a secondaryimage-forming lens, an aperture stop, a line sensor including aplurality of CCD sensors and the like, which are not shown in FIG. 5.The AF sensor unit 204 is configured so as to be able to perform focusdetection on 45 areas of the object field at the locations of the focusdetection areas 50 to 94 in the viewfinder visual field, which has beenalready described with reference to FIGS. 4A and 4B.

Then, based on a control signal output from the system controller 223, afocus detection circuit 205 controls the AF sensor unit 204 to performfocus detection by conventional phase difference detection.

On the other hand, the image-taking light flux reflected by thequick-return mirror 202 reaches the eyes of the photographer via apentaprism 201 and the eyepiece 206.

When the quick-return mirror 202 is moved up, the light flux from theimage-taking lens 101 reaches an image-pickup element 210 such as a CCDsensor and a CMOS sensor, via a focal plane shutter 208 which is amechanical shutter, and a filter 209.

It should be noted that although a solid state image-pickup element suchas a CCD sensor and a CMOS sensor is used in this embodiment, it ispossible to use a silver halide film or an image-pickup tube such as avidicon.

The filter 209 has the following two functions. One is to block infraredrays and to guide only visible rays to the image-pickup element 210. Theother is to serve as an optical low-pass filter. In addition, the focalplane shutter 208 includes a front curtain and a rear curtain, andtransmits and blocks the light flux from the image-taking lens 101.

Additionally, when the quick-return mirror 202 is moved up, the submirror 203 is folded against the quick-return mirror 202.

Furthermore, the camera body 200 of this embodiment is provided with thesystem controller 223 (hereinafter, also occasionally referred to as“CPU 223”) constituted by a CPU which serves to control the entireoperation of the digital camera, and appropriately controls theoperations of various sections which will be described later.

The system controller 223 is connected to: a lens control circuit 104which controls a lens driving mechanism 103 for performing focusing bymoving the image-taking lens 101 in the optical axis direction; anaperture control circuit 106 which controls an aperture drivingmechanism 105 for driving the aperture stop 102; a shutter charge-mirrordriving mechanism 211 which controls the driving of the up and downmovements of the quick-return mirror 202 and the driving of the shuttercharge of the focal plane shutter 208; a shutter control circuit 212 forcontrolling the movement of the front curtain and the rear curtain ofthe focal plane shutter 208; a photometry circuit 207 connected to aphotometry sensor (not shown) disposed in the vicinity of the eyepiece206; and an EEPROM 222 serving as a storage section which storesparameters necessary to be adjusted to control the digital camera 200,camera ID information which enables individual identification of thedigital camera, AF correction data adjusted with a reference lens, anauto exposure compensation value and the like.

The lens control circuit 104 also includes a lens storage circuit whichstores information unique to the lens, such as a focal length, openaperture and a lens ID assigned to an individual lens, and informationreceived from the system controller 223.

The photometry sensor connected to the photometry circuit 207 is asensor for measuring the brightness of the object, and its output issupplied to the system controller 223 from the photometry circuit 207.

The system controller 223 controls the lens driving mechanism 103 toform an object image on the image-pickup element 210. In addition, thesystem controller 223 controls the aperture driving mechanism 105 fordriving the aperture stop 102 based on a set Av value, and also outputsa control signal to the shutter control circuit 212 based on a set Tvvalue.

The driver of the front curtain and the rear curtain of the focal planeshutter 208 is constituted by a spring, and it is necessary to chargethe spring after a shutter movement for the subsequent operation. Theshutter charge-mirror driving mechanism 211 controls this springcharging. The shutter charge-mirror driving mechanism 211 also moves thequick-return mirror 202 up and down.

Further, the system controller 223 is connected to an image datacontroller 220. The image data controller 220 is constituted by a DSP(digital signal processor) and performs, for example, the control of theimage-pickup element 210 and the correction or process of image datainput from the image-pickup element 210, in accordance with commandsfrom the system controller 223. The items of the correction and processof the image data include auto white balance. Auto white balance is thefunction of correcting a portion of an obtained image which has thehighest brightness to have a predetermined color (white). The correctionamount for the auto white balance can be changed in accordance withcommands from the system controller 223.

The image data controller 220 is connected to: a timing pulse generatingcircuit 217 which outputs a pulse necessary for driving the image-pickupelement 210; an A/D converter 216 for receiving, together with theimage-pickup element 210, a timing pulse generated with the timing pulsegenerating circuit 217 and converting an analog signal corresponding toan object image output from the image-pickup element 210 to a digitalsignal; a DRAM 221 which temporarily stores the obtained image data(digital data); a D/A converter 215; and an image compression circuit219.

The DRAM 221 is used for temporarily storing image data before the imagedata is processed or converted to a predetermined format.

The D/A converter 215 is connected to the LCD monitor unit 213 via anencoder circuit 214. Furthermore, the image compression circuit 219 isconnected to the recording medium 218.

The LCD monitor unit 213 is a circuit for displaying image data obtainedwith the image-pickup element 210, and is ordinarily constituted by acolor liquid crystal display device.

The image data controller 220 converts image data in the DRAM 221 intoan analog signal with the D/A converter 215,and outputs the signal tothe encoder circuit 214. The encoder circuit 214 converts the outputfrom the D/A converter 215 into a video signal (e.g., an NTSC signal)which is necessary for driving the LCD monitor unit 213.

The image compression circuit 219 is a circuit for performingcompression or conversion (e.g., JPEG) of image data stored in the DRAM221. The converted image data is stored in the recording medium 218.Examples of such a recording medium include hard disks, flash memoriesand flexible disks.

Furthermore, the system controller 223 is connected to: an operationdisplay circuit 225 for displaying operation mode information, exposureinformation (e.g., the shutter speed and the aperture value) and thelike of the digital camera on the external liquid crystal display unit250 or the internal liquid crystal display unit 251; the main electronicdial 226; an AF correction confirmation button 227; a focus detectionarea selection button 235 for selecting a focus detection position usedduring focus detection from a plurality of focus detection positionswhich the AF sensor unit 204 has; the image-taking mode selection button229 with which the user sets a mode for causing the digital camera toexecute a desired operation; the release SW1 (231) for starting apreparatory operation for image-taking, such as photometry and focusdetection; the release SW2 (230) for starting an image-taking operation;the AF mode selection button 233; and the photometry mode selectionbutton 235.

In the following, the operation flow of the digital camera configured asabove is described with reference to FIGS. 6 to 9. FIG. 6 is a flowchartshowing the displaying process of an identification mark according tothe present invention. Referring to FIG. 6, in step (abbreviated as “S”in the figure) 101, it is detected whether the lens apparatus 100 hasbeen mounted on the camera body 200. If it is determined that the lensapparatus 100 has been mounted, the procedure advances to step 102.

In step 102, the system controller 223 communicates with the lenscontrol circuit 104 to receive lens ID information, and the procedureadvances to step 103.

In step 103, the system controller 223 communicates with the EEPROM 222to determine whether the obtained lens ID information is stored in theEEPROM 222. If the system controller 223 determines as a result ofcommunicating with the EEPROM 222 that the obtained lens ID informationis stored, it determines that the correction amount for focus correctionhas already been calculated for the currently mounted lens apparatus100, and the procedure advances to step 104.

On the other hand, if the system controller 223 determines as a resultof communicating with the EEPROM 222 that the obtained lens IDinformation is not stored, it determines that a lens apparatus for whichthe focus correction amount has not been calculated is mounted, and theprocedure advances to step 108.

If it is determined in step 103 that a lens apparatus for which thefocus correction amount has already been calculated is mounted and thenthe procedure has advanced to step 104, a timer set for a predeterminedtime is started in step 104, and the procedure advances to step 105.

In step 105, a correction amount identification mark and an AFcorrection amount is displayed on the external liquid crystal displayunit 250 and the internal liquid crystal display unit 251.

Here, the display of the correction amount identification mark and theAF correction amount is described with reference to FIGS. 7A to 7D.FIGS. 7A and 7B show a display state of the external liquid crystaldisplay unit 250 and the internal liquid crystal display unit 251 when alens apparatus 100 for which the focus correction amount has beencalculated is mounted.

Referring to FIG. 7A, section 250 h indicates a correction amountidentification mark indicating that the focus correction amount has beencalculated, and 250 b indicates the calculated focus correction amount(unit: μm). In FIG. 7A, it is indicated that the focus position has beencorrected by +20 μm.

Referring to FIG. 7B, section 251 e indicates a correction amountidentification mark indicating that the focus correction amount has beencalculated, and 251 f denotes a calculated focus correction amount(unit: μm). In FIG. 7B, it is indicated that the focus position has beencorrected by +20 μm.

Displaying the correction amount identification mark in this way allowsthe photographer to recognize that focus correction is performed for thecombination of the camera body and the lens apparatus, so that thephotographer can perform image-taking comfortably.

Referring again to FIG. 6, after displaying the correction amountidentification mark in step 105, the procedure advances to step 106, inwhich it is determined whether the timer started in step 104 hasexpired. If it is determined that the timer has not expired, theprocedure returns to step 105, and the correction amount identificationmark continues to be displayed.

On the other hand, if it is determined that the timer has expired, theprocedure advances to step 107, in which the correction amountidentification mark displayed in step 105 is turned off, and theprocedure returns to a preparatory state for image-taking. Since thecorrection amount identification mark is displayed only for apredetermined time after mounting the lens apparatus in this way, it ispossible to eliminate inconvenience which would have been caused whenthe correction amount identification mark is displayed every time duringimage-taking.

If it is determined in step 103 that a lens apparatus 100 for which thefocus correction amount has not yet been calculated is mounted, theprocedure advances to step 108, in which the correction amountidentification mark blinks. Here, the display format is described withreference to FIGS. 7C and 7D. FIGS. 7C and 7D show a display state ofthe external liquid crystal display unit 250 and the internal liquidcrystal display unit 251 when a lens apparatus 100 for which the focuscorrection amount has not been calculated is mounted.

As shown in FIGS. 7C and 7D, since the correction amount identificationmarks 250 h and 251 e blink, the photographer can easily recognize thata lens apparatus for which the focus correction amount has not beencalculated, i.e., a lens apparatus for which focus correction is notperformed is mounted, so that it is possible to avoid the problem thatthe photographer continues to take images in a state in which in-focushas not been established.

Although a warning display is provided to the photographer by lettingthe correction amount identification marks 250 h and 251 e blink in thisembodiment, it is also possible to disable the image-taking operation,instead of providing a warning display. A warning may also be providedby producing sounds, or vibrating the camera.

Referring again to FIG. 6, after letting the correction amountidentification marks blink in the step 108, it is determined in step 109whether the AF mode is set to the manual focus mode by operating the AFmode selection button 233. Then, if it is determined that the manualfocus mode is not selected, the procedure returns to step 108, in whichthe correction amount identification marks is continued to blink.

On the other hand, if it is determined that the manual focus mode isselected, the procedure advances to step 107, in which the correctionamount identification marks are turned off. If the manual focus mode isselected, focus adjustment is carried out by the photographer, so thatit is not necessary to notify the photographer that focus correction isnot performed. That is, it is not necessary to cause the identificationmark to blink. Accordingly, it is possible to eliminate inconveniencesfor the photographer by turning off the identification mark.

Although the identification mark is displayed for a predetermined periodafter mounting the lens apparatus in this embodiment, the identificationmark may be displayed every time during image-taking. Further, althoughthe identification mark is displayed on both the external liquid crystaldisplay unit 250 and the internal liquid crystal display unit 251 inthis embodiment, the identification mark may be displayed on only one ofthem.

Embodiment 2

A method according to this embodiment for displaying a correction amountidentification mark in a case where the AF correction confirmationbutton 2 is pressed is described with reference to the flowchart of FIG.8. It should be noted that the camera system of this embodiment has thesame structure as Embodiment 1, so that the description has been omittedhere.

Referring to FIG. 8, it is determined in step 201 whether the AFcorrection confirmation button 2 is pressed. If it is determined thatthe AF correction confirmation button 2 is not pressed, thedetermination is repeated until the AF correction confirmation button 2is pressed.

On the other hand, if it is determined that the AF correctionconfirmation button 2 is pressed, the procedure advances to step 202, inwhich the system controller 223 communicates with the lens controlcircuit 104 to receive lens ID information, and the procedure advancesto step 203.

In step 203, the system controller 223 communicates with the EEPROM 222to determine whether the obtained lens ID information is stored. If thesystem controller 223 determines as a result of communicating with theEEPROM 222 that the obtained lens ID information is stored, itdetermines that the correction amount for focus correction has beencalculated for the mounted lens apparatus 100, and the procedureadvances to step 204.

On the other hand, if the system controller 223 determines as a resultof communicating with the EEPROM 222 that the obtained lens IDinformation is not stored, it determines that a lens apparatus for whichthe focus correction amount has not been calculated is mounted, and theprocedure advances to step 208.

If it is determined in step 203 that a lens apparatus for which thefocus correction amount has already been calculated is mounted and thenthe procedure advances to step 204, a timer set for a predetermined timeis started in step 204, and the procedure advances to step 205.

In step 205, an identification mark and a correction amount aredisplayed on the external liquid crystal display unit 250 and theinternal liquid crystal display unit 251. The method for displaying theidentification mark is performed as shown in FIGS. 7A and 7B as inEmbodiment 1.

After displaying the correction amount identification mark in step 205,the procedure advances to step 206, and it is determined whether thetimer started in step 204 has expired. If it is determined that thetimer has not expired, the procedure returns to step 205, in which thecorrection amount identification mark continues to be displayed.

On the other hand, if it is determined that the timer has expired, theprocedure advances to step 207, in which the correction amountidentification mark displayed in step 205 is turned off, and theprocedure returns to a preparatory state for image-taking. In step 203,if it is determined that a lens apparatus for which the focus correctionamount has not been calculated is mounted, the procedure advances tostep 208, in which the timer is started, and the procedure advances tostep 209.

In step 209, a display as shown in FIGS. 7C and 7D is provided, and theprocedure advances to step 210. A warning may also be provided byproducing sounds, or vibrating the camera.

In step 210, it is determined whether the timer started in step 208 hasexpired. If it is determined that the timer has not expired, theprocedure returns to step 209, in which the blinking of the correctionamount identification mark is continued.

On the other hand, if it is determined in step 210 that the timer hasexpired, the procedure advances to step 207, in which the correctionamount identification mark is turned off.

Thus, since the correction amount identification mark is displayed onlywhen the correction confirmation button 2 is pressed, it is possible toeliminate inconvenience which would have been caused when the correctionamount identification mark is displayed every time.

Embodiment 3

A method according to this embodiment for displaying a correction amountidentification mark corresponding to a focus detection area is describedwith reference to the flowchart of FIG. 9. It should be noted that thecamera system of this embodiment has the same structure as Embodiment 1,so that components that are same as those in Embodiment 1 are given thesame reference numerals and their description has been omitted.

In step 301 in FIG. 9, it is detected whether the focus detection areaselection switch 228 is turned ON. If it is determined that the focusdetection area selection switch 228 is not turned ON (in OFF state), thedetection is repeated until the focus detection area selection switch228 is turned ON. On the other hand, if it is determined the focusdetection area selection switch 228 is turned ON, the procedure advancesto step 302.

In step 302, it is detected whether the main electronic dial 226 hasbeen operated. If the main electronic dial 226 has been operated, theoperated direction and the operated amount are detected.

In step 303, the superimposed display of the focus detection areas 50 to94 in the viewfinder visual field which are already described in FIGS.4A and 4B is changed in accordance with the operated direction and theoperated amount of the main electronic dial 226 detected in step 302.The selection order is as follows: all, focus detection area 50, focusdetection area 51 . . . focus detection area 94, all.

In step 304, it is determined whether the AF correction amount has beencalculated in the focus detection area(s) selected in step 303. Then, ifit is determined that the AF correction amount has been calculated, theprocedure advances to step 305, in which the superimposed display isturned on.

On the other hand, if it is determined in step 304 that the AFcorrection amount has not been calculated, the procedure advances tostep 306, in which the blinking of the superimposed display isperformed.

Here, a specific displaying method of steps 305 and 306 is describedwith reference to FIGS. 10A and 10B.

10A shows a state in which a focus detection area for which the AFcorrection amount has been calculated is selected. As shown in FIG. 10A,the focus detection area 72 is turned on, and, furthermore, thecorrection amount identification mark 251 e is also turned on.

Further, FIG. 10B shows a state in which a focus detection area forwhich the AF correction amount has not been calculated is selected. Asshown in FIG. 10B, the focus detection area 74 is displayed in ablinking state, and, furthermore, the correction amount identificationmark 251 e is also displayed in a blinking state.

In FIG. 9, after completion of steps 305 and 306, the procedure advancesto step 307, in which it is determined whether the focus detection areaselection switch 228 is turned ON. Then, if it is determined that thefocus detection area selection switch 228 is turned ON, the procedurereturns to step 302 and the above-described operations are repeated,because the focus detection area selection sequence is still beingexecuted.

On the other hand, if it is determined in step 307 that the focusdetection area selection switch 228 is not turned ON (in OFF state), theprocedure terminates the focus detection area selection sequence.

As described above, the focus detection area and the correction amountidentification mark blinks when a focus detection area for which the AFcorrection amount has not been calculated is selected, so that thephotographer can readily recognize that a focus detection area for whichthe AF correction amount has not been calculated is selected. It shouldbe noted that although whether the AF correction is performed isdetermined by lighting or blinking the focus detection area and thecorrection amount identification mark in this embodiment, this may alsobe done by changing the color of the focus detection area and thecorrection amount identification mark.

Embodiment 4

Simultaneous recording of a correction amount identification mark and animage file according to Embodiment 4 of the present invention isdescribed with reference to FIGS. 11A and 11B.

In step 401, it is determined whether the release SW1 (231) is turnedON. If it is determined that the release SW1 (231) is turned ON, theprocedure branches to step 402 of determining the image-taking exposureand to step 404.

In step 402, photometry is performed on a light flux which has passedthrough the image-taking lens 101, been reflected by the quick-returnmirror 202 and passed through the pentaprism 201, with the photometrycircuit 207. In step 403, the system controller 223 determines theexposure amount during image-taking in accordance with the output fromthe photometry circuit 207.

In step 404, the system controller 223 performs focus detection, usingthe AF sensor unit 204 and the focus detection circuit 205.

In step 405, the system controller 223 determines whether it waspossible to detect the focus state. When the object on which focusdetection was performed is low-contrast or dark, it may not be possibleto detect the focus state. If it was possible to detect the focus state,the procedure advances to step 406, in which a warning is provided.

In step 407, the system controller 223 receives lens ID information, andit determines whether the AF correction amount (CAL data) of the focusdetection area used in focus detection which corresponds to the lensapparatus mounted on the digital camera 200 (as determined from the lensID) is stored in the EEPROM. If it determines that the AF correctionamount (CAL data) is not stored, then no AF correction amount is addedto the result of focus detection. If it determines that the AFcorrection amount (CAL data) is stored, then the AF correction amount(CAL data) is added to the result of focus detection in step 409, andthe procedure advances to step 410.

If the AF correction data (CAL data) is already present, the lensdriving amount is as follows:

Lens driving amount=focus detection result+AF correction amount(adjustment data) during manufacturing+AF correction amount (CAL data)

In step 410, based on the result of focus detection, the systemcontroller 223 transmits a lens driving amount to the lens controlcircuit 104, and the lens control circuit 104 controls the lens drivingmechanism 103 based on the transmitted lens driving amount. Then, thelens driving mechanism 103 drives the image-taking lens 101 to anin-focus position.

In step 411, it is determined whether the release SW2 (230) is turnedON. If it is determined that the release SW2 (230) is turned ON, theprocedure advances to step 412.

In step 412, the system controller 223 controls the shuttercharge-mirror driving mechanism 211 such that the quick-return mirror202 and the sub mirror 203 are moved up so as to be retracted from theimage-taking optical path.

In step 413, the system controller 223 transmits the aperture valueinformation set in step 403 to the aperture control circuit 106, anddrives the aperture driving mechanism 105 to narrow down the aperturevalue to the set value. Then, the procedure advances to step 414.

In step 414, the system controller 223 controls various sections to openthe focal plane shutter 208. Further, in step 415, the system controller223 directs the image data controller (DSP) 220 to perform chargeaccumulation on the image-pickup element 210. In step 416, the procedurewaits for a predetermined time. Then, after the predetermined time isover, the procedure advances to step 417, in which the focal planeshutter 208 is closed.

In step 418, the system controller 223 carries out the chargingoperation of the focal plane shutter 208 and the operation of moving themirrors down, in preparation for the next image-taking operation. Instep 419, the aperture stop is driven to the open position.

In step 420, the system controller 223 directs the image data controller220 to read image data from the image-pickup element 210.

In step 421, the image data read from the image-pickup element 210 iscompressed with the image compression circuit 219, and the image dataand the correction amount identification mark are stored in therecording medium 218 in association with each other.

Here, the display state in the case where the image data described inFIGS. 11A and 11B is reproduced is described in detail with reference toFIGS. 12A and 12B. FIGS. 12A and 12B are diagrams showing the state whenobtained images are reproduced on the LCD monitor unit 213. In FIGS. 12Aand 12B, reference numeral 501 denotes an image reproduced on the LCDmonitor unit 213.

In addition, together with the obtained images, a shutter speed 502, anaperture value 503, an image-taking mode 506, a photometry mode 507, anISO sensitivity 508, a white balance mode 509, an image-takingdate/image-taking time 510, a file number 511, a recording image quality505, a histogram 512 and a correction amount identification mark 513 aredisplayed on the LCD monitor unit 213 as the image-taking information.Furthermore, reference numeral 514 indicates a focus detection areaselected as described in FIG. 9 which is superimposed with red.

FIG. 12A shows a state in which an image taken in a focus detection areafor which the AF correction amount has been calculated is reproduced. Inthis case, the focus detection area 514 and the correction amountidentification mark 513 are turned on.

On the other hand, FIG. 12B show a state in which an image obtained in afocus detection area for which the AF correction amount has not beencalculated is reproduced. In this case, the focus detection area 514 andthe correction amount identification mark 513 are displayed in ablinking state.

Thus, by storing the correction amount identification mark and theobtained image in association with each other, it is possible to blinkthe focus detection area 514 and the correction amount identificationmark 513 at the time of reproduction in the case where the image wasobtained in a focus detection area for which the AF correction amounthas not been calculated, thus allowing the photographer to easilyrecognize this.

It should be noted that although whether the image was obtained in afocus detection area for which the AF correction amount has not beencalculated is indicated by lighting or blinking the focus detection area514 and the correction amount identification mark 513 in thisembodiment, it is also possible to allow the photographer to recognizethis by changing their colors.

As described above, with the present invention, it is possible todetermine whether information on accessories (e.g., a lens apparatus andan illumination apparatus) mounted on the camera, i.e., information usedwhen performing a control corresponding to the accessory is stored in astorage section. Then, a signal corresponding to the result of thedetermination, including, for example, an image signal, an audio signal,a signal causing vibration and a combination of these signals, isoutput, so that it is possible to readily determine whether theinformation on the accessory is stored in the storage section based onthis signal.

Furthermore, by using, as the above-described information, correctioninformation for correcting a calculation result for control inaccordance with the accessory, it is possible to readily determinewhether the correction information which is necessary for the accessoryis stored in the storage section based on a signal corresponding to theresult of the determination.

Further, by letting the controller perform operations to obtaincorrection information in a state in which an accessory is mounted onthe camera, and storing the obtained correction information in thestorage section in association with the accessory, it is possible toreliably store the correction information corresponding to the accessoryin the storage section.

Additionally, by providing a display unit which provides a display basedon a signal, it is possible to visually determine whether theinformation on the accessory is stored in the storage section, withaccuracy.

Further, in the present invention, an accessory mounted on the camera isidentified. Then, whether information corresponding to the identifiedaccessory, i.e., information used when performing a controlcorresponding to the accessory is stored in a storage section, and imagedata obtained by the camera using the accessory and the result of thedetermination are recorded in a recording medium in association witheach other. Accordingly, it is possible to store the presence or absenceof information corresponding to the accessory and the obtained imagedata in relation to each other. This makes it possible to determine, atthe time of reproducing the obtained image, whether the image wasobtained in a state in which the correction was performed. In addition,since the presence or absence of the information corresponding to theaccessory is recorded in the recording medium which stores data ofobtained images, this information can be stored for a large number ofobtained images in the camera system.

Further, by using, as the above-described information, correctioninformation for correcting the result of the calculation for control inaccordance with the accessory, the presence or absence of the correctioninformation which is necessary in relation to the accessory can bestored in association with the obtained image data.

Further, by letting the controller perform operations to obtaincorrection information in a state in which an accessory is mounted onthe camera, and storing the obtained correction information inassociation with the accessory in the storage section, it is possible toreliably store the correction information corresponding to the accessoryin the storage section.

Furthermore, in the present invention, a lens apparatus mounted on thecamera is identified, and it is determined whether correctioninformation corresponding to the identified lens apparatus, that is,correction information for correcting a calculation result in focusadjustment control is stored in a storage section. Then, a signalcorresponding to the result of the determination, such as a videosignal, an audio signal or a signal which causes vibration, is output.Therefore, it is possible to determine based on this signal whethercorrection information for focus adjustment associated with the lensapparatus is stored in the camera system, so that image-taking can beperformed in a favorable focus condition.

By letting the controller perform operations to obtain correctioninformation in a state where a lens apparatus is mounted on the camera,and storing the obtained correction information in the storage sectionin association with the lens apparatus, it is possible to reliably storethe correction information necessary for focus adjustment in associationwith the lens apparatus.

Additionally, by providing a display unit which provides a display basedon a signal, it is possible to visually determine the presence orabsence of correction information for correcting a calculation resultobtained by focus detection control corresponding to the lens apparatus.

The possibility of overlooking the presence or absence of the correctioninformation can be reduced by changing the display format of the displayunit.

The presence or absence of the correction information can be reliablydisplayed on the display unit before image-taking, by providing adetector which detects the mounted state of the lens apparatus on thecamera, and letting the controller perform the above-describeddetermination if the detector detects that the lens apparatus ismounted.

The presence or absence of the correction information can be displayedon the display unit based on the intention of the user, by providing anoperation unit which lets the controller perform the above-describeddetermination in accordance with the operation by the user. That is, thephotographer can check the display unit only when he or she wishes to doso, and the presence or absence of the correction information is notdisplayed on other occasions. This eliminates inconvenience which wouldhave been caused when the presence or absence of correction informationis displayed every time, so that the photographer can concentrate onimage-taking.

If the correction information is not stored in the storage section, itis possible to reliably allow the user to recognize that the correctioninformation is not stored, by providing a warning display with thedisplay unit.

By providing a focus selection unit which selects between manual focusand autofocus, and performing the above-described determination onlywhen autofocus is selected, a warning display is not provided every timeduring manual focusing, so that the photographer can concentrate onfocusing.

Since the image-taking operation of the camera is restricted if it isdetermined that the correction information is not stored in the storagesection, it is possible to disable image-taking when the focus isdisplaced.

Furthermore, in the present invention, a lens apparatus mounted on thecamera is identified, and whether correction information correspondingto the identified lens apparatus is stored in the storage section. Then,image data obtained with the camera using the lens apparatus and theresult of the determination are recorded in association with each otherin the recording medium. Accordingly, the presence or absence ofinformation corresponding to the lens apparatus and the obtained imagedata can be stored in relation to each other. This makes it possible todetermine, at the time of reproducing the obtained image, whether theimage was taken in a state in which the correction for focus adjustmentwas performed. In addition, since the presence or absence of thecorrection information is recorded in the recording medium which storesobtained image data, this information can be stored for a large numberof obtained images in the camera system.

Further, by letting the controller perform operations to obtaincorrection information in a state in which a lens apparatus is mountedon the camera, and storing the obtained correction information inassociation with the lens apparatus in the storage section, it ispossible to reliably store the correction information in the storagesection.

By providing a display unit which displays obtained image data recordedin the recording medium and letting the display unit display the resultof the determination together with the obtained image data, it ispossible to determine, at the time of reproducing the obtained image,whether the image was taken in a state in which focus adjustment wasperformed.

Embodiment 5

FIG. 13 is a functional block diagram of a camera system according toEmbodiment 5 of the present invention. In FIG. 13, reference numeral 301denotes a camera, and a lens apparatus 303 capable of zooming is mountedat the center on the front of the camera 301, via a mount 301 aindicated by the dashed line.

First, the structure of the lens apparatus 303 is described. Referencenumeral 311 denotes a lens MPU (micro processing unit), 312 denotes alens driving unit for driving an image-taking lens 316 in the opticalaxis direction, and 313 denotes an aperture driving unit for opening andclosing aperture blades 317 in a plane substantially orthogonal to theoptical axis. Additionally, in FIG. 13, the solid lines connecting theblocks indicate electrical connection, and the dotted lines indicatemechanical connection.

Reference numeral 314 denotes a first storage section constituted by anEEPROM (electrically erasable and programmable read only memory) servingas an electrically rewritable nonvolatile memory. The first storagesection 314 stores a correction amount (fourth information) obtained bymounting the lens apparatus 303 on a reference camera described below.The details of the fourth information will be described later.

Reference numeral 315 denotes a lens memory which stores individualinformation assigned to each individual lens apparatus. In thisembodiment, a model number specifying the model of a lens apparatus anda serial number of each lens apparatus are used as the individualinformation. It is also possible to provide a memory in the lens MPU311, and to store the above-described individual information in thememory. Here, the individual information can be any information whichcan specify each individual lens apparatus. For example, instead ofusing the model number, it is possible to use a serial number which isunique across all models, or a unique number such as a channel.

Next, the structure of the camera 301 is described. Reference numeral321 denotes a camera MPU which can communicate with the lens MPU 311.The camera MPU 321 can obtain, from the lens MPU 311, the correctionamount stored in the first storage section 314 and the individualinformation of the lens apparatus mounted on the camera 301.

Reference numeral 322 denotes a focus detection sensor for detecting adefocus amount used for focus control of the image-taking lens, using alight flux entering the image-taking lens, and 323 denotes a shutterdriving unit which drives a shutter (not shown).

Reference numeral 324 denotes an image-pickup element (e.g., a CCDsensor and a CMOS image sensor) which generates an image signal byphotoelectrically converting a light flux entering the image-takinglens. Reference numeral 325 denotes a dial unit for setting varioussettings (e.g., the shutter speed, the aperture value and theimage-taking mode) of the camera.

Reference numeral 326 denotes a second storage section constituted by anEEPROM (electrically erasable and programmable read only memory) servingas an electrically rewritable nonvolatile memory. The second storagesection 326 stores a correction amount (third information) obtained bymounting a reference lens apparatus (a specific lens apparatus)described below on the camera 301, individual information of a pluralityof lens apparatuses selectively mounted on the camera 301, and acorrection amount (second information) associated with the individualinformation of each of the lens apparatuses.

More specifically, the second storage section 326 stores correctionamounts corresponding to a plurality of lens apparatuses which can bemounted on the camera 301. For example, it stores individual informationA and a correction amount associated with the individual information A,individual information B and a correction amount associated with theindividual information B . . . individual information N and a correctionamount associated with the individual information N.

Reference numeral SW1 (330) denotes a switch which is turned ON by afirst stroke operation of (half pressing) a release button (not shown),and SW2 (331) denotes a switch which is turned ON by a second strokeoperation of (fully pressing) the release button (not shown).

When the SW1 is turned ON, the focus detection sensor 322 is driven, anda focus detection operation is started. When the SW2 is turned ON,exposure of the image-pickup element 324 and recording of the imagesignal photoelectrically converted with the image-pickup element 324 ina recording medium (not shown) are started.

The defocus amount, that is the difference between the image-formingposition of the image-taking lens and the position of the image surfaceat which the image-taking operation is performed, necessary forautofocus adjustment is calculated from the displacement amount(prediction amount) of two images formed respectively by light fluxesfrom the object which pass through two different areas flanking theoptical axis of the image-taking lens.

Specifically, the light fluxes of the two images pass through a mainmirror 328 which is formed as a half mirror and disposed obliquely in animage-taking optical path, then reflected toward a lower position of thecamera 301 by a sub mirror 329 disposed on the image surface side withrespect to the main mirror 328, and guided to the focus detection sensor322 by a focus detection optical system (not shown). Incidentally, thelight fluxes reflected by the main mirror 328 form image on a focusingscreen 332, and the image is observed through a pentamirror 333 and aviewfinder lens 334.

The focus detection sensor 322 serves as a photoelectrical conversionelement, from which the camera MPU 321 reads signals of the two imagesand calculates the displacement amount of the images by performingcorrelation calculation, thereby determining a defocus amount.

The autofocus adjustment is carried out in the above-described manner.However, the image-taking optical system of the lens apparatus variesdepending on the model, so that even when the object is at an in-focusposition, the defocus amount is not necessarily 0, depending on themodel of the lens apparatus. Further, even when the design defocusamount is 0, the defocus amount is not necessarily 0 for everyindividual lens apparatus because of the discrepancy of the image-takingoptical system.

For this reason, the defocus amount is measured in advance using apre-adjusted reference camera in a state in which focus has beenachieved on a light-receiving surface of the image-pickup element 324 ina lens calibration step at the factory. This defocus amount is stored asthe correction amount in the first storage section 314 of the lensapparatus 303, as described above.

In an actual operation, the camera MPU 321 communicates with the lensMPU 311 at the time of autofocus adjustment, obtains the correctionamount stored in the first storage section 314 through communication,and subtracts this correction amount from the defocus amount detectedwith the focus detection sensor 322.

Similarly, due to the discrepancy of the focus detection optical system,the defocus amount is not necessarily 0 for every camera even when theobject is at an in-focus position. For this reason, the defocus amountis measured in advance using a pre-adjusted reference lens in a state inwhich focus has been achieved on a light-receiving surface of theimage-pickup element 324 in a camera calibration step at the factory.Then, this defocus amount is stored as a correction amount in the secondstorage section 326 in the camera 301, as described above.

Specifically, the flange focal length (the distance from a surface ofthe mount 301 a to the light-receiving surface of the image-pickupelement 324) of the camera is measured first, and the amount ofdeviation from the design value is determined. Next, a reference lenswhich has been focused in advance on a reference chart at a knowndistance is corrected by the amount of displacement of the flange focallength. Subsequently, the reference chart is placed at the center of thesensor, and the defocus amount is determined. This defocus amount iswritten as a correction amount in the second storage section 326.

In an actual operation, the camera MPU 321 reads the correction amountstored in the second storage section 326 at the time of autofocusadjustment, and subtracts this correction amount from the defocus amountdetected by the focus detection sensor 322.

In the following, the method for correcting a defocus amount of thecamera system according to this embodiment is described with referenceto the flowchart of FIG. 14.

First, in step S1101, the camera MPU 321 reads an object image from thefocus detection sensor 322 and calculates a defocus amount. Here,examples of the method for detecting the defocus amount include phasedifference detection and TV-AF method, and any of such methods may beused.

Next, in step S1102, the camera MPU 321 reads from the second storagesection 326, the correction amount determined using the reference lens,and corrects the defocus amount obtained in step S1101.

Subsequently, in step S1103, by communicating with the lens MPU 311, thecamera MPU 321 reads the correction amount determined using thereference camera and stored in the first storage section 314, andcorrects the corrected defocus amount obtained in step S1102.

The procedure advances to step S1104, in which the camera MPU 321 readsthe individual information by communicating with the lens MPU 311 anddetermines whether the individual information is stored in the secondstorage section 326 of the camera 301. If the individual information isstored, the procedure advances to step S1105, in which the camera MPU321 reads from the second storage section 326, the correction amountstored in association with that individual information and corrects thedefocus amount obtained in step S1103.

Thus, the defocus amount obtained with the focus detection sensor 322 iscorrected with the correction amount determined using the referencecamera and stored in the first storage section 314 and the correctionamount determined using the reference lens and stored in the secondstorage section 326, and the result of this correction is furthercorrected with the correction amount corresponding to the individualinformation assigned to each individual lens apparatus. Therefore, evenif a plurality of lens apparatuses of the same model is selectivelymounted on the camera, it is possible to perform correctioncorresponding to the mounted lens apparatus. This makes it possible toimprove the focusing accuracy of the image-taking lens. On the otherhand, if the individual information is not stored in the second storagesection 326, the camera MPU 321 does not perform any correction, and theprocedure advances to step S1106, terminating the correction process ofthe defocus amount.

Embodiment 6

FIG. 15 is a functional block diagram of a camera system according tothis embodiment. The structural components that are the same as those ofEmbodiment 5 are given the same reference numerals, and theirdescription has been omitted.

The camera system of this embodiment is different from that ofEmbodiment 5 in that the lens MPU 311 corrects the defocus amount, usingindividual information of the camera.

Reference numeral 327 denotes a camera memory which stores individualinformation provided to each individual camera. In this embodiment, acamera model number specifying the model of a camera and a camera serialnumber specifying an individual camera which belongs to the camera modelnumber are used as the individual information. Similarly to Embodiment5, it is possible to use any information, as long as it can specify eachindividual camera. Additionally it is also possible to provide a memoryin the camera MPU 321, and to store the above-described individualinformation in the memory.

The first storage section 314 of the lens apparatus 303 stores acorrection amount obtained by mounting the lens apparatus 303 on areference camera, individual information of a camera on which the lensapparatus 303 can be mounted, and a correction amount associated withthe individual information. The second storage section 326 of the camera301 stores a correction amount obtained by mounting a reference lens onthe camera 301.

In the following, a method for correcting the defocus amount of thecamera system according to this embodiment is described.

First, the lens MPU 311 reads an object image from the focus detectionsensor 322 and calculates a defocus amount. Here, examples of the methodfor detecting the defocus amount include phase difference detection andTV-AF method, and any of such methods may be employed.

Then, the lens MPU 311 reads from the second storage section 326, thecorrection amount determined using the reference lens and corrects theabove-described defocus amount detected with the focus detection sensor322. Thus far, the correction method is the same as in Embodiment 5.

Next, the lens MPU 311 further corrects the corrected defocus amount inaccordance with the flowchart shown in FIG. 16. More specifically, instep S1201, the lens MPU 311 reads the correction amount determinedusing the reference camera and stored in the first storage section 314,and obtains the read correction amount by communication in step S1202.At this time, the lens MPU 311 does not perform the above-describedprocess of correcting the corrected defocus amount using the correctionamount obtained by communication, and the procedure advances to stepS1203.

In step S1203, the lens MPU 311 reads the individual information storedin the camera memory 327 by communicating with the camera MPU 321, anddetermines whether the individual information is stored in the firststorage section 314. If the individual information is stored in thefirst storage section 314, the procedure advances to step S1204, inwhich the lens MPU 311 reads from the first storage section 314, thecorrection amount stored in association with the individual informationand adds this correction amount to the correction amount obtained instep S1202. Accordingly, it is possible to obtain an effect similar tothat of Embodiment 5.

On the other hand, if the individual information is not stored, the lensMPU 311 adds nothing to the correction amount obtained in step S1202,and the procedure advances to step S1205, in which the lens MPU 311corrects the defocus amount with the correction amount obtained in stepS1202.

According to the present invention, it is possible to provide a cameracapable of performing focus control of the image-taking lens, using thesecond information associated with individual information assigned toeach individual lens apparatus mounted on the camera. This makes itpossible to perform focus control corresponding to the individualinformation of each lens apparatus even in the case where a plurality oflens apparatuses which differ in individual information is selectivelymounted on the camera, thus improving focusing accuracy.

Embodiment 7

FIG. 17 is a block diagram showing the structures of an electroniccamera 1200 and a lens apparatus 1100 of a camera system according toEmbodiment 7 of the present invention.

As shown in FIG. 17, the lens apparatus 1100 is removably mounted on theelectronic camera 1200 via a mount mechanism (not shown). A group ofelectrical contacts 1107 is provided to the mount mechanism, andcommunication is carried out between the electronic camera 1200 and thelens apparatus 1100 to drive an image-taking lens 1101 and an aperturestop 1102 in the lens apparatus 1100.

An image-taking light flux from an object is guided to a quick-returnmirror 1202 via the image-taking lens 1101 and the aperture stop 1102for adjusting the light quantity. The central part of the quick-returnmirror 1202 is formed as a half mirror, through which a portion of theobject light flux is transmitted at a position (the position shown inFIG. 17) where the quick-return mirror 1202 is moved down. Then, aportion of the object light flux transmitted through the quick-returnmirror 1202 is reflected by a sub mirror 1203 disposed on the backsurface of the quick-return mirror 1202, and guided to an AF sensor1204.

The image-taking light flux reflected by the quick-return mirror 1202reaches the eyes of the photographer, via a pentaprism 1201 and aneyepiece 1206.

Furthermore, when the quick-return mirror 1202 is moved up and the submirror 1203 is folded and moved up, the image-taking light flux from theimage-taking lens 1101 reaches an image sensor 1210, which is typicallya CMOS sensor or the like, serving as an image-pickup element, via afocal plane shutter 1208 which is a mechanical shutter, and a filter1209. The filter 1209 has the following two functions. One is to blockinfrared rays and to guide only visible rays to the image sensor 1210.The other is to serve as an optical low-pass filter which blockshigh-frequency components of the object light. In addition, the focalplane shutter 1208 includes a front curtain and a rear curtain, andtransmits and blocks the light flux from the image-taking lens 1101.

The electronic camera 1200 is provided with a system controller 1223constituted by a CPU for controlling the entire electronic camera 1200,and appropriately control the operation of each of the section describedlater.

The system controller 1223 is connected to: a lens control circuit 1104which controls a lens driving mechanism 1103 for performing focusing bymoving the image-taking lens 1101 in the optical axis direction; anaperture control circuit 1106 which controls an aperture drivingmechanism 1105 for driving the aperture stop 1102; a shuttercharge-mirror driving mechanism 1211 which controls the driving of theup and down movements of the quick-return mirror 1202 and the driving ofthe shutter charge of the focal plane shutter 1208; a shutter controlcircuit 1212 for controlling the movement of the front curtain and therear curtain of the focal plane shutter 1208; a photometry circuit 1207for performing auto exposure control which is connected to a photometrysensor (not shown) provided in the vicinity of the eyepiece 1206; and anEEPROM 1222 which stores parameters necessary to be adjusted to controlthe electronic camera 1200, camera ID information which enablesindividual identification of the electronic camera 1200, AF correctiondata adjusted with a reference lens, auto exposure compensation valuesand the like. Additionally, the system controller 1223 controls AF(autofocus adjustment), AE (auto exposure adjustment) and the bracketingimage-taking for white balance.

The lens control circuit 1104 is provided with a storage section whichstores information unique to the individual lens, such as a focallength, open aperture value and a lens ID assigned to each individuallens, a lens type, manufacturer information, and a lens condition, aswell as information received from the system controller 1223.

Furthermore, the electronic camera 1200 can be connected to an externalcontrol apparatus 1300, which is typically a personal computer (PC), andthe external control apparatus 1300 and the system controller 1223 cancommunicate with each other via a communications interface circuit 1224.

FIG. 18 is a diagram showing an image-taking field.

This image-taking field is also an image range observed from theviewfinder. The image-taking field is divided into, for example, threephotometry areas 1, 2 and 3, and photometry is carried out for each ofthe divided areas. Furthermore, the three photometry areas 1, 2 and 3include focus detection areas 1, 2 and 3, respectively, and focusdetection is performed at three positions on the image-taking field withthe AF sensor 1204 provided with three sensor sections correspondingrespectively to these focus detection areas 1, 2 and 3.

In FIG. 17, the photometry sensor connected to the photometry circuit1207 is a sensor for measuring the brightness of the object, and itsoutput is supplied to the system controller 1223 via the photometrycircuit 1207. The photometry section of the photometry sensor measuresthe light intensity in each of the photometry areas 1 to 3 shown in FIG.18. The photometry circuit 1207 performs auto exposure adjustment.

Further, the system controller 1223 controls the lens driving mechanism1103 via the lens control circuit 1104 to form an object image on theimage sensor 1210. In addition, based on an Av value set in theimage-taking mode described later, the system controller 1223 controlsthe aperture driving mechanism 1105 via the aperture control circuit1106 to drive the aperture stop 1102 and also outputs a control signalto the shutter control circuit 1212, based on a set Tv value.

The driver of the front curtain and the rear curtain of the focal planeshutter 1208 is constituted by a spring, and it is necessary to chargethe spring after a shutter movement for the subsequent operation. Theshutter charge-mirror driving mechanism 1211 is configured so as tocontrol this spring charging. The shutter charge-mirror drivingmechanism 1211 also moves the quick-return mirror 1202 up and down.

The system controller 1223 is connected to an image data controller1220. The image data controller 1220 constituted by a DSP (digitalsignal processor) performs, for example, the control of the image sensor1210, and the correction or process of image data input from the imagesensor 1210, in accordance with commands from the system controller1223. The items of the correction/process of the image data include autowhite balance. The auto white balance is the function of correcting aportion of an obtained image which has the highest brightness to apredetermined color (white). The correction amount for the auto whitebalance can be changed in accordance with commands from the systemcontroller 1223.

The image data controller 1220 is connected to: a timing pulsegenerating circuit 1217 which outputs a pulse necessary for driving theimage sensor 1210: an A/D converter 1216 for receiving a timing pulsegenerated with the timing pulse generating circuit 1217 and convertingan analog signal corresponding to an object image output from the imagesensor 1210 to a digital signal; a DRAM 1221 which temporarily storesthe image data (digital data) obtained with the A/D converter 1216; aD/A converter 1215; and an image compression circuit 1219.

The DRAM 1221 temporarily stores image data before the image data isprocessed or converted to a predetermined format.

The D/A converter 1215 is connected to an image display circuit 1213 fordisplaying an image via an encoder circuit 1214. The image compressioncircuit 1219 is connected to an image data recording medium 1218.

The image display circuit 1213 is a circuit for displaying image dataobtained with the image sensor 1210, and includes a color liquid crystaldisplay device.

The image data controller 1220 reads image data on the DRAM 1221 and theread image data is converted into an analog signal with the D/Aconverter 1215 for output to the encoder circuit 1214. The encodercircuit 1214 converts the output from the D/A converter 1215 into avideo signal (e.g., an NTSC signal) which is necessary at the time ofdriving the image display circuit 1213.

The image compression circuit 1219 is a circuit for performingcompression or conversion (e.g., JPEG) of image data stored in the DRAM1221. The converted image data is stored in the image data recordingmedium 1218. Examples of the image data recording medium 1218 includehard disks, flash memories and floppy (trademark) disks.

Furthermore, the system controller 1223 is connected to: a displaycircuit 1225 for displaying operation mode information, exposureinformation (e.g., a shutter speed and an aperture value) and the likeof the electronic camera 1200; a release SW1 (1231) for starting apreparatory operation for image-taking, such as photometry and focusdetection; a release SW2 (1230) for starting an image-taking operation,a mode setting switch 1229 with which the user sets a mode for lettingthe electronic camera 1200 execute a desired operation; a focusdetection area selection switch 1228 for starting a process of selectinga focus detection area to be used from the three focus detection areas(focus detection positions) 1 to 3 corresponding to the three sensorsections of the AF sensor 1204; a determination switch 1227 forselecting an image, a bracketing amount setting switch 1232 for settinga bracketing amount; a photometry area selection switch 1235 forstarting a process of selecting a photometry area to be used from thethree photometry areas 1 to 3 shown in FIG. 18; and an electronic dialswitch 1226 for increasing or decreasing parameters by rotatingoperation. A counter 1233 is a counter for counting the number ofrelease times at the time of performing various modes of bracketingimage-taking, and connected to the system controller 1223. The reset ofa discrete value of the counter 1233 is performed with the systemcontroller 1223.

In the following, the principle of the defocus amount (focus positiondisplace amount) detection is described with reference to FIGS. 19A to19C and FIG. 20.

FIGS. 19A to 19C are diagrams showing the interval between two images ona line sensor in the focused state and the defocused state.

As shown in FIG. 19A, when focus is achieved on the image-pickup element(in-focus state), the interval between two images on the line sensorassumes a given value. Although this value can be determined in design,an actual value will not be the same as a design value because of thepresence of variations in dimensions of parts, errors in assembly andthe like. Therefore, the interval between two images in the focusedstate (reference interval between two images Lo) needs to be obtained bymeasurement. It should be noted that, as shown in FIGS. 19B and 19C,when the interval between two images is narrower than the referenceinterval between two images Lo, the focus state is front focus. When itis wider, the focus state is rear focus.

FIG. 20 is a diagram showing the interval between two images in a modelwhich corresponds to the AF sensor module optical system shown in FIGS.19A to 19C from which a condenser lens has been omitted.

As shown in FIG. 20, where θ represents the angle of the principal ray,β represents the magnification of the separator lens, ΔL represents themovement amount of the image on an equivalent surface of theimage-pickup element and ΔL′ represents the movement amount of the imageon the line sensor, the defocus amount “d” can be determined by thefollowing Equation (1):d=ΔL/tan θ=ΔL′/(β·tan θ)   (1)where (β·tan θ) represents a parameter determined in designing the AFsensor module.

The movement amount ΔL′ can be determined from the reference interval oftwo images Lo and the present interval of two images Lx (ΔL′=Lo×Lx).

Based on this principle of the defocus amount (focus positiondisplacement amount) detection, the method performed in the camerasystem shown in FIG. 17 for correcting variations in focus positionamong individual image-taking lenses is described below.

Conventionally, in focus adjustment of autofocus function, animage-taking lens whose focus position has been already known is used,and a focus position is set at a position (a position including errorsoccurring at the time of mounting the image-pickup element) on theoptical axis of the image-pickup element. Then, the interval between twoimages obtained from the AF sensor at that time is stored as an AF focuscorrection parameter in the EEPROM. However, in the case where aplurality of lens apparatuses are mounted on an electronic camera,variations occur in their focus positions, since manufacturing errorsare present in the lens apparatuses themselves.

Therefore, in the system controller 1223 of the present invention, an AFcalibration mode, which is a correction amount calculation mode ofcalculating and setting a correction amount for correcting the focusposition, is used to calculate an AF correction amount for eachindividual lens apparatus based on information obtained from the AFsensor 1204 for performing focus detection and information concerningthe lens apparatus mounted on the electronic camera 1200, thus making itpossible to correct variations among the lens apparatuses.

Before describing the calculation of the AF correction amount and thecorrection of variations in focus position among the lens apparatuses, afocus detection area selection process and a photometry area selectionprocess are described.

FIG. 21 is a flowchart showing the procedure of the focus detection areaselection process executed with the system controller 1223 of theelectronic camera 1200.

In step S2001, the procedure waits until the focus detection areaselection switch 1228 is turned ON. When it is turned ON, the procedureadvances to step S2002.

In step S2002, the procedure waits until the electronic dial switch 1226is operated. When it is operated, the procedure advances to step S2003.

In step S2003, in accordance with the operation of the electronic dialswitch 1226, the focus detection area is switched to the subsequent areaamong the focus detection areas 1 to 3 shown in FIG. 18 in accordancewith a switching order. The switching order is: all, focus detectionarea 1, focus detection area 2, focus detection area 3, all, or thereverse of this order, depending on the rotating direction of theelectronic dial switch 1226. Each time the electronic dial switch 1226is rotated, the area to be selected is switched in the above-describedorder.

In step S2004, it is determined whether the focus detection areaselection switch 1228 is still ON, and the procedure returns to stepS2002 if it is ON, and terminates the focus detection area selectionprocess if it is not ON.

FIG. 22 is a flowchart showing the procedure of a photometry areaselection process executed with the system controller 1223 of theelectronic camera 1200.

In step S2501, the procedure waits until the photometry area selectionswitch 1235 is turned ON. When it is turned ON, the procedure advancesto step S2502.

In step S2502, the procedure waits until the electronic dial switch 1226has been operated. When it has been operated, the procedure advances tostep S2503.

In step S2503, in accordance with the operation of the electronic dialswitch 1226, the photometry area is switched to the subsequent area in aswitching order among the photometry areas 1 to 3 shown in FIG. 18. Theswitching order is: all, the photometry area 1, the photometry area 2,the photometry area 3, all, or the reverse of this order, depending onthe rotating direction of the electronic dial switch 1226. Each time theelectronic dial switch 1226 is rotated, the area to be selected isswitched in the above-described order.

In step S2504, it is determined whether the photometry area selectionswitch 1235 is still ON, and the procedure returns to step S2502 if itis ON, and terminates the photometry area selection process if it is notON.

FIGS. 23 and 24 are flowcharts showing the procedure of the process forsetting an image-taking mode and an AF calibration mode executed withthe system controller 1223 of the electronic camera 1200.

In step S2101, the procedure waits until the mode setting switch 1229has been turned ON. When it has been turned ON, it is determined that amode setting operation is started by the user, and the procedureadvances to step S2102.

In step S2102, the system controller 1223 determines whether a lensapparatus is mounted on the electronic camera 1200 and whether acorrection amount calculation process by the AF calibration mode can beperformed on the mounted lens apparatus, based on the information uniqueto the lens obtained from the lens control circuit of the mounted lensapparatus, such as a focal length, open aperture value, a lens IDassigned to each individual lens, a lens type, manufacturer informationand information on lens conditions.

If the system controller 1223 determines as a result of thedetermination that no lens apparatus is mounted on the electronic camera1200, it determines that the selective setting of the AF calibrationmode is not possible, and the procedure advances to step S2106 forsetting a regular image-taking mode. On the other hand, if the systemcontroller 1223 determines that the lens apparatus 1100 is mounted onthe electronic camera 1200 and the correction amount calculation processby the AF calibration mode is possible, the procedure advances to stepS2103 for setting a regular image-taking mode or an AF calibration mode.If the system controller 1223 determines that the lens apparatus 1100 ismounted on the electronic camera 1200, but the correction amountcalculation process by the AF calibration mode is not possible, theprocedure advances to step S2106.

Further, in step S2102, the system controller 1223 determines that theselective setting of the AF calibration mode is not possible, dependingon the type of the lens apparatus mounted on the electronic camera 1200,that is, in the cases where the following lens apparatuses are mountedon the electronic camera 1200.

(1) Lens apparatus for manual focusing only: in the case of using thislens apparatus, it is not possible to drive the image-taking lens basedon focus detection with the AF sensor 1204 and a focus detection circuit1205, so that it is not possible to calculate a correction amount forcorrecting a focus position by autofocus detection.

(2) Lens apparatus capable of performing one or both of shift-drivingand tilt-driving of the image-taking lens: in the case of using thislens apparatus, a portion of the image-taking optical system isshift-driven or tilt-driven, so that the image-taking optical axis ismoved in parallel or tilted, with respect to the optical axiscorresponding to the center of the image plane. Accordingly, the lightflux entering the AF sensor 1204 differs from an ordinary light flux, sothat it is not possible to accurately perform autofocus detection withthe focus detection circuit 1205. Consequently, it is not possible tocalculate an accurate correction amount for correcting a focus positionby autofocus detection.

(3) Lens apparatus for macro image-taking only which is provided with animage-taking magnification of 1× or higher: in the case of using thislens apparatus, the movement amount of the focusing lens is large, sothat the camera has the characteristics that the change in F valueincreases from infinity (the lowest magnification) toward the shorterdistance (higher magnification) side and the F value is extremely largeon the higher magnification side. Accordingly, it is impossible toperform autofocus detection with the AF sensor 1204 and the focusdetection circuit 1205, so that it is not possible to calculate acorrection amount for correcting a focus position by autofocusdetection.

(4) Lens apparatus manufactured by a different manufacturer from that ofthe electronic camera 1200: in the case of using this lens apparatus, itis not possible to ensure that the information unique to the lens, suchas a lens ID assigned to each individual lens, which is stored in thelens control circuit 1104 of the lens apparatus 1100 assumes a correctvalue specified by the manufacturer of the electronic camera 1200.Accordingly, it is not possible to calculate a correction amount forcorrecting a focus position by autofocus detection.

(5) Lens apparatus in which abnormality or failure occurs: in the caseof using this lens apparatus, it is expected that accurate lensinformation cannot be obtained from the lens control circuit 1104 andthat communication between the system controller 1223 and the lenscontrol circuit 1104 cannot to be established, so that it is notpossible to calculate a correction amount for correcting a focusposition by autofocus detection.

It should be noted that the AF calibration mode is not selectable unlessonly one of the focus detection areas 1 to 3 is selected by the focusdetection area selection process shown in FIG. 21.

In step S2106, the procedure waits until the electronic dial switch 1226for mode selection has been operated. When the electronic dial switch1226 has been operated, the image-taking mode is cyclically changed to“Tv”, “Av”, “P”, “Tv” . . . , in accordance with the rotating operation.When the electronic dial switch 1226 is reversely rotated, theimage-taking mode is cyclically changed to “Tv”, “P”, “Av” , “Tv” . . ., in accordance with the rotating operation.

In step S2107, it is determined whether the mode setting switch 1229turned ON in step S2101 has been turned OFF. The procedure advances tostep S2108 if it has been turned OFF, or returns to step S2106 if it isstill ON.

In step S2108, the currently selected image-taking mode is set in theelectronic camera 1200, and the procedure advances to an image-takingprocess (not shown) corresponding to the set image-taking mode.

In step S2103, the procedure waits until the electronic dial switch 1226for mode selection has been operated. When the electronic dial switch1226 has been operated, the image-taking mode and the AF calibrationmode are cyclically changed to “Tv”, “Av” , “P”, “AF calibration”, “Tv”. . . , in accordance with the rotating operation. When the electronicdial switch 1226 is reversely rotated, the image-taking mode and the AFcalibration mode are cyclically changed to “Tv”, “AF calibration”, “P”,“Av”, “Tv” . . . , in accordance with the rotating operation.

In step S2104, it is determined whether the mode setting switch 1229turned ON in step S2101 has been turned OFF. The procedure advances tostep S2105 if it has been turned OFF, or returns to step S2103 if it isstill ON.

In step S2105, the currently selected image-taking mode or AFcalibration mode is set in the electronic camera 1200, and the procedureadvances to step S2109.

In step S2109, it is determined whether the set mode is the AFcalibration mode. The procedure advances to step S2110 if the set modeis the AF calibration mode, or advances to an image-taking process (notshown) corresponding to the image-taking mode if it is the image-takingmode.

In step S2110, it is determined again whether a lens apparatus ismounted on the electronic camera 1200 and whether a correction amountcalculation process by the AF calibration mode can be performed on themounted lens apparatus, based on the information unique to the lenswhich is obtained from the lens control circuit 1104 of the mounted lensapparatus. The reason why such determination is made again is thatdespite that the AF calibration mode is set, there is the possibilitythat the lens apparatus may have been replaced with one of the lensapparatuses (1) to (5) described in step S2102, that the lens apparatusmay have been removed, or that an abnormality may have occurred in themounted lens apparatus for some reason.

If it is determined in step S2109 that the AF calibration mode is set,and in step S2110 that a lens apparatus is mounted on the electroniccamera 1200 and a correction amount calculation process by the AFcalibration mode can be performed on the lens apparatus, the procedureadvances to step S2111 to start preparing for image-taking in the AFcalibration mode. On the other hand, if it is determined in step S2109that the AF calibration mode is set, and in step S2110 that a lensapparatus is mounted on the electronic camera 1200, but a correctionamount calculation process by the AF calibration mode cannot beperformed on the lens apparatus, the procedure advances to step S2117.

In step S2117, a warning is provided to the user. Thereafter, the AFcalibration mode is cancelled in step S2118, and the procedure returnsto the image-taking mode setting process (step S2101 in FIG. 23).

Additionally, the warning to the user in step S2117 is given byproviding, for example, a warning display on an external display of theelectronic camera 1200 with a display circuit 1225, a warning display ona display in the viewfinder, an audio notification with a beeper 1234,or disabling the image-taking process by, for example, disabling theshutter release.

In step S2111, it is determined whether the bracketing amount settingswitch 1232 has been turned ON, in order to set the AF bracketing amountduring AF calibration image-taking. The procedure advances to step S2112if it has been turned ON, or advances to step S2116 if it has not beenturned ON.

In step S2116, the AF bracketing amount during an AF calibrationimage-taking is set to the reference set value “a”, and the procedureadvances to the AF calibration image-taking process shown in FIG. 25.

In step S2112, it is determined whether the electronic dial switch 1226has been operated. The procedure advances to step S2113 if theelectronic dial switch 1226 has been operated, or returns to step S2111if it has not been operated. If the electronic dial switch 1226 has beenoperated, the AF bracketing step amount is changed to “reference valuea×0.25”, “reference value a×0.5”, “reference value a”, “reference valuea×2”, “reference value a×4”, or in the reversed direction, in accordancewith the rotating operation. However, “reference value×0.25” and“reference value×4” are defined as the lower limit and the upper limit,respectively, and the AF bracketing step amount will not be changed to avalue exceeding these limits even when the electronic dial switch 1226is operated.

The reference value “a” of the AF bracketing step amount has beencalculated by the system controller 1223 based on the following Equation(2), using open aperture value information (FNO) received from theaperture control circuit 1106.Reference value a=d=FNO×e   (2)where e represents the permissible diameter of circle of confusion.

The reference value of this embodiment is defined as the same as thevalue of: depth of focus d=FNO×e. In this embodiment, it is defined thate=0.03 mm.

As described above, the user can freely set the AF bracketing stepamount by turning the bracketing amount setting switch 1232 ON, so thatit is possible to narrow down the focus correction amount to anappropriate value by performing the AF calibration for a plurality oftimes while gradually changing the step amount (from a larger stepamount to a smaller step amount), even when a significant focuscorrection is required.

In step S2113, it is determined whether the bracketing amount settingswitch 1232 turned ON in step S2111 has been turned OFF. The procedureadvances to step S2114 if it has been turned OFF, or returns to stepS2112 if it is still ON.

In step S2114, the currently selected AF bracketing step amount is takenas a bracketing step amount “A” to be set.

Thereafter, the procedure advances to the AF calibration image-takingprocess shown in FIG. 25.

FIGS. 25 and 26 are flowcharts showing the procedures of the AFcalibration image-taking process executed with the system controller1223 of the electronic camera 1200.

In step S2201, the counter 1233 is reset.

In step S2202, the procedure waits until the release SW1 (1231) has beenturned ON, and advances to steps S2203 and S2205 when it has been turnedON.

In step S2203, using the photometry circuit 1207, photometry isperformed on a light flux which has passed through the image-taking lens1101, been reflected by the quick-return mirror 1202 and passed throughthe pentaprism 1201. In step 2204, the system controller 1223 determinesthe exposure amount during image-taking, in accordance with the outputfrom the photometry circuit 1207.

In step S2205, the system controller 1223 performs focus detection,using the AF sensor 1204 and the focus detection circuit 1205.

In step S2206, it is determined whether it was possible to detect thefocus state. When the object on which the focus detection is performedis low-contrast or dark, it may not be possible to detect the focusstate. If it was not possible to detect the focus state, the procedureadvances to step 2210, in which a warning is provided. If it waspossible to detect the focus state, the procedure advances to stepS2207.

In step S2207, based on the focus detection result obtained in step2205, the system controller 1223 transmits a lens driving amount to thelens control circuit 1104, and the lens control circuit 1104 controlsthe lens driving mechanism 1103 based on the transmitted lens drivingamount. Then, the lens driving mechanism 1103 drives the image-takinglens 1101 to a focus position. At this time, if there is an AFcorrection amount (CAL data) already present (this will be described indetail later in step S2407 of FIG. 29), the lens driving amount can beobtained by the following Equation (3):Lens driving amount=focus detection result+AF correction amount(adjustment data) during manufacturing+AF correction amount (CAL data)  (3)In step S2208, the focus position of the image-taking 1101 which hasbeen obtained by the lens driving in step S2207 is set as the AFreference position, which is stored by the system controller 1223. Then,in step S2209, the system controller 1223 directs the image datacontroller 1220 to create a folder for storing AF calibration image datain the image data recording medium 1218, and the image data controller1220 creates the folder for storing AF calibration image data in theimage data recording medium 1218 via the image compression circuit 1219.

In step S2211, the procedure waits until the release SW2 (1230) has beenturned ON, and advances to step S2212 when it has been turned ON.

In step S2212, the system controller 1223 receives the current countnumber “N” from the counter 1233 and calculates a focus position shiftamount “DF” based on the following Equation (4):DF=A×(N−4)   (4)As described above, “A” represents the bracketing step amount set instep S2114.

In step S2213, the count number “N” of the counter 1233 is counted up by1.

In step S2214, the system controller 1223 transmits the focus positionshift amount “DF” calculated in step S2212 to the lens control circuit1104, and the lens control circuit 1104 controls the lens drivingmechanism 1103 to drive the image-taking lens 1101 to a position shiftedby the focus position shift amount “DF”.

In step S2215, the system controller 1223 controls the shuttercharge-mirror driving mechanism 1211 to move the quick-return mirror1202 up.

In step S2216, the system controller 1223 transmits aperture valueinformation to the aperture control circuit 1106 based on the exposureamount determined in step S2204, and drives the aperture drivingmechanism 1105 to narrow down the aperture value to the set value.

In step S2217, the system controller 1223 controls various sections toopen the focal plane shutter 1208. Further, in step S2218, the systemcontroller 1223 directs the image data controller 1220 to perform anintegration operation of the image sensor 1210. In step S1219, theprocedure waits for a predetermined integration time. Then, after anelapse of the predetermined integration time, the procedure advances tostep S2220, in which the focal plane shutter 1208 is closed.

In step S2221, the system controller 1223 carries out the chargingoperation of the focal plane shutter 1208 and the driving of moving themirrors down, in preparation for the next image-taking operation. Instep S2222, the aperture stop 1102 is driven to the open position. Instep S2223, the system controller 1223 directs the image data controller1220 to capture image data from the image sensor 1210. At that time, theimage data obtained from the image sensor 1210 may be image data withina limited area including the focus detection area used for focusdetection.

In step S2224, the system controller 1223 transmits the current focusposition shift amount “DF” to the image data controller 1220. Uponreceiving this, the image data controller 1220 records the lens IDinformation, the image data and the focus position shift amount “DF” inassociation with one another in the image data recording medium 1218,via the image compression circuit 1219.

In step S2225, it is determined whether the count number “N” of thecounter 1233 has reached a predetermined value (e.g., 7). If the countnumber “N” has reached a predetermined number, the AF calibrationimage-taking process is terminated and the procedure advances to theimage selection process shown in FIG. 27. If the count number “N” hasnot reached a predetermined number, the procedure returns to step S2211.

FIGS. 27 and 28 show flowcharts showing the procedure of the imageselection process in the AF calibration which is executed with thesystem controller 1223 of the electronic camera 1200.

In step S2301, the system controller 1223 controls the image datacontroller 1220 such that the image data whose count number “N” is “i”,which was obtained in the AF calibration image-taking process shown inFIGS. 25 and 26, is displayed with the image display circuit 1213. Whendisplaying image data, the image display circuit 1213 performs an imageprocessing different from that performed when displaying an imageobtained by a regular image-taking process. More specifically, whendisplaying an image obtained by a regular image-taking process, edgeenhancement process is carried out in order to improve the appearance ofthe image. However, when edge enhancement process is performed on imagedata obtained in the AF calibration mode, a portion of the image whichis actually out of focus appears as if it is in focus. For this reason,there is the possibility that an image which is out of focus may beselected erroneously at the time of selecting an image which is inoptimum focus from a group of images obtained in the AF calibrationmode, so that an image processing different from that performed whendisplaying an image obtained by a regular image-taking process isperformed.

In step S2302, it is determined whether the determination switch 1227has been turned ON by a user who has seen the image displayed in stepS2301 and determined that the image is in optimum focus. If it has beenturned ON, the procedure advances to step S2313. If it has not beenturned ON, the procedure advances to step S2303.

In step S2303, the operated state of the electronic dial switch 1226 isdetected. The procedure advances to step S2304 if the electronic dialswitch 1226 has been rotated leftward, or advances to step S2308 if ithas been rotated rightward.

In step S2304, the count number “N” of the counter 1233 is counted downby only “1”. In step S2305, it is determined whether the count number“N” is less than “0”. The procedure advances to step S2306 if it is lessthan “0”, or advances to step S2312 if it is equal to or greater than“0”.

In step S2306, a warning that there is no AF calibration image datawhich can be selectively displayed is provided, using at least one ofthe image display circuit 1213 and the beeper 1234. In the subsequentstep S2307, the count number “N” of the counter 1233 is counted up byonly “1”, and the procedure returns to step S2303.

In step S2308, the count number “N” of the counter 1233 is counted up byonly “1”. In step S2309, it is determined whether the count number “N”is greater than “7”. The procedure advances to step S2311 if it isgreater than “7”, or advances to step S2312 if it is equal to or lessthan “7”.

In step S2311, a warning that there is no AF calibration image datawhich can be selectively displayed is provided, using at least one ofthe image display circuit 1213 and the beeper 1234. In the subsequentstep S2310, the count number “N” of the counter 1233 is counted down byonly “1”, and the procedure returns to step S2303.

In step S2312, the AF calibration image data corresponding to thecurrent count number “N” of the counter 1233 is called up from the imagedata recording medium 1218 and displayed with the image display circuit1213, and the procedure returns to step S2302.

In step S2313, the focus position shift amount “DF” recorded in theimage data recording medium 1218 in association with the AF calibrationimage data displayed when the determination switch 1227 has been turnedON in step S2302 is determined as the AF correction amount (CAL data)for the focus detection area on which focus detection was performed. Inthe subsequent step S2314, the focus position shift amount “DF”determined as the AF correction amount (CAL data) in step S2313 iswritten in the EEPROM 1222, together with the lens ID of the lenscontrol circuit 1104.

In step S2315, the entire AF calibration image data and the folder forAF calibration image data which have been stored in the image datarecording medium 1218 are deleted.

FIGS. 29 and 30 are flowcharts showing the procedure of the regularimage-taking process executed with the system controller 1223 of theelectronic camera 1200.

In step S2401, the procedure waits until the release SW1 (1231) has beenturned ON, and advances to steps S2402 and S2404 when it has been turnedON.

In step S2402, using the photometry circuit 1207, photometry isperformed on a light flux which has passed through the image-taking lens1101, been reflected by the quick-return mirror 1202 and passed throughthe pentaprism 1201. In step 2403, the system controller 1223 determinesthe exposure amount during image-taking in accordance with the outputfrom the photometry circuit 1207.

In step S2404, the system controller 1223 performs focus detection,using the AF sensor 1204 and the focus detection circuit 1205.

In step S2405, it is determined whether it was possible to detect thefocus state. When the object on which the focus detection is performedis low-contrast or dark, it may not be possible to detect the focusstate. If it was not possible to detect the focus state, the procedureadvances to step 2409, in which a warning is provided. If it waspossible to detect the focus state, the procedure advances to stepS2406.

In step S2406, the system controller 1223 receives lens ID informationfrom the lens control circuit 1104, and references the EEPROM 1222 todetermine whether the AF correction amount (CAL data) of the focusdetection area used in focus detection which corresponds to the lens IDinformation is stored. If it is stored, the procedure advances to stepS2407, in which the system controller 1223 adds (makes a calculationbased on the above-described Equation (3)) the AF correction amount (CALdata) to the focus detection result obtained in step S2404, and theprocedure advances to step S2408. If the AF correction amount (CAL data)is not stored in the EEPROM 1222, the system controller 1223 does notadd the AF correction amount to the focus detection result (step S2407is skipped), and the procedure advances to step S2408.

In step S2408, based on the focus detection result (to which the AFcorrection amount may have been added), the system controller 1223transmits a lens driving amount to the lens control circuit 1104, andthe lens control circuit 1104 controls the lens driving mechanism 1103based on the transmitted lens driving amount. Then, the lens drivingmechanism 1103 drives the image-taking lens 1101 to a focus position.

In step S2410, the procedure waits until the release SW2 (1230) has beenturned ON, and advances to step S2411 when it has been turned ON.

The processes performed in steps S2411 to S2420 are the same as thoseperformed in steps S2215 to S2224 shown in FIG. 26, so that theirdescription have been omitted here.

In this embodiment, a folder for AF calibration is created in the imagedata recording medium 1218, and a plurality of AF calibration images arestored in the folder. The plurality of AF calibration images and thefolder are deleted upon completion of the lens driving after the userhas selected an image from the plurality of AF calibration images andthe AF correction amount has been determined. However, if there isenough room in the memory capacity of the image data recording medium1218, the plurality of AF calibration images and the folder may not haveto be erased upon completion of the AF calibration. In that case, it isnot necessary to create the folder in step S2209 of FIG. 25, and todelete the plurality of AF calibration images and the folder in stepS2315 of FIG. 28.

In addition, although the AF correction amount (CAL data) is stored inthe EEPROM 1222 of the electronic camera 1200 in this embodiment, the AFcorrection amount (CAL data) alternatively may be stored in a memorycircuit provided in the lens control circuit 1104 of the lens apparatus1100, together with the camera ID information and the focus detectionarea information.

Further, in this embodiment, the image display is performed with theimage display circuit 1213 of the electronic camera 1200 at the time ofexecuting the image selection process shown in FIGS. 27 and 28.Alternatively, however, the image display process and the imageselection process may be performed with the external control apparatus1300 by sending image data to the external control apparatus 1300 viathe communications interface circuit 1224.

Furthermore, although each process is executed with the systemcontroller 1223 of the electronic camera 1200 in this embodiment,similar effects can also be achieved when the external control apparatus1300 executes each process by controlling the system controller 1223 viathe communications interface circuit 1224.

Although the AF bracketing amount is determined based on the open Fvalue of the lens apparatus 1100 in this embodiment, the AF bracketingamount alternatively may be varied according to the focal length of theimage-taking lens 1101. In the case where the image-taking lens 1101 isa zoom lens, the AF correction amount (CAL data) may be determined ateach focal length and stored in the EEPROM 1222.

As described above, in this embodiment, image-taking is performed for aplurality of times while changing the focus position, and the pluralityof image data obtained are recorded in the image data recording medium1218 in association with focus position shift amounts. After completionof image-taking, an image which is in optimum focus is selected from therecorded plurality of image data by the user, and the focus positionshit amount recorded in association with the selected image data isstored as the AF correction amount (CAL data). This process is performedfor each lens apparatus, and autofocusing is carried out by correcting afocus detection result with the AF correction amount (CAL data)corresponding to the mounted lens apparatus, in regular image-taking.Accordingly, it is possible to obtain an image which is in optimum focusfor each lens apparatus. Furthermore, the user can easily correct thefocus position.

Moreover, it is possible to obtain a more accurate focus positioncorrection amount (AF correction amount) by varying the focus positionshift amount.

It is also possible to allow the user to easily correct themanufacturing errors of cameras and lens apparatuses to achievefavorable conditions.

Furthermore, at the time of reading image data from an image sensor(image-pickup element), only image data of a selected focus detectionarea is read, so that the time required for image reading can be saved.

Since a folder which stores image data obtained during calculation ofcorrection data is created for this purpose only, the problem that theimage data is mistaken for image data obtained in regular image-takingwill not occur.

Furthermore, since image data obtained during calculation of correctiondata is deleted after calculating the AF correction amount (CAL data),it is possible to utilize the image data recording medium effectively.

Since the AF correction amount (CAL data) is recorded in the EEPROM 1222of the electronic camera 1200 in association with the lens ID and thefocus detection area, it is possible to record the AF correction amount(CAL data) for each lens apparatus and for each focus detection area.This effect can also be achieved when the AF correction amount (CALdata) is recorded in the memory circuit of the lens apparatus 1100 inassociation with the lens ID and the focus detection area.

Embodiment 8

In the following, Embodiment 8 of the present invention is described.

The constitution of this embodiment is basically the same as that ofEmbodiment 7. Therefore, in this embodiment, the same reference numeralsand description are applied to parts that are the same as those in theconstitution of Embodiment 7, and only parts that are different aredescribed.

In this embodiment, the contents of the setting processes of theimage-taking mode and the AF calibration mode shown in FIGS. 23 and 24partially differ from those of Embodiment 7.

In this embodiment, similarly to Embodiment 7, the system controller1223 determines in step S2102 shown in FIG. 23 whether a lens apparatusis mounted on the electronic camera 1200 and whether a correction amountcalculation process by the AF calibration mode can be performed on themounted lens apparatus based on the lens information obtained from thelens control circuit of the mounted lens apparatus.

Further, the system controller 1223 determines in step S2102 of thisembodiment that the selective setting of the AF calibration mode is notpossible, depending on the setting state of the lens apparatus mountedon the electronic camera 1200, that is, in the cases where the followingsetting states of the lens apparatus are detected.

(1) In the case where it is detected that an AF correction amount hasalready been set, by the AF calibration mode (correction amountcalculation mode), for a lens apparatus in which an AF correction amountcan be set: in this case, setting a new AF calibration mode may resultin the possibility that an improper correction amount may be calculatedby erroneous operations and this improper correction amount may bemistaken for the already existing accurate correction amount.Accordingly, the already existing correction amount is lost, and it isnot possible to obtain an accurate focus detection result in regularimage-taking.

(2) In the case where it is detected that a manual focus mode is set fora lens apparatus that can be switched between a manual focus mode and anautofocus mode: in this case, it is impossible to drive the image-takinglens based on focus detection with the AF sensor 1204 and the focusdetection circuit 1205, so that it is not possible to calculate acorrection amount for correcting a focus position detected by autofocusdetection.

(3) In the case where it is detected that one or both of shift-drivingand tilt-driving are set for a lens apparatus capable of performing oneor both of shift-driving and tilt-driving of the image-taking lens: inthis case, since a portion of the image-taking optical system isshift-driven or tilt-driven, the image-taking optical axis is moved inparallel or tilted, with respect to the optical axis corresponding tothe center of the image plane. Accordingly, a light flux entering the AFsensor 1204 differs from an ordinary light flux, so that it is notpossible to accurately detect the focus state by autofocus detectionwith the focus detection circuit 1205. Consequently, it is not possibleto calculate an accurate correction amount for correcting a focusposition by autofocus detection.

(4) In the case where it is detected that a macro mode is set for a lensapparatus capable of setting a macro mode which provides an image-takingmagnification of 1× or higher: in this case, the movement amount of thefocusing lens is large, so that the camera has the characteristics thatthe change in F value increases from infinity (the lowest magnification)toward the shorter distance (higher magnification) side and the F valueis extremely large on the higher magnification side. Accordingly, it isimpossible to perform autofocus detection with the AF sensor 1204 andthe focus detection circuit 1205, so that it is not possible tocalculate a correction amount for correcting a focus position byautofocus detection.

(5) In the case where it is detected that a focusing lens in the mountedlens apparatus is driven outside a predetermined object distance range:since various optical aberrations generally occur owing to variations infocus position of the lens apparatus, it is preferable to set apredetermined focus position and to correct the focus position byautofocus detection. Further, when autofocus detection with the focusdetection circuit 1205 is performed based on an object located inpositions (infinity end, closest end) at which the focus position isextremely moved, a large error occurs in a focus detection result and anaccurate detection result cannot be obtained, so that it is not possibleto calculate an accurate correction amount for correcting a focusposition by autofocus detection.

(6) In the case where it is not possible to obtain accurate lens settinginformation from the lens control circuit 1104, or to establishcommunication between the system controller 1223 and the lens controlcircuit 1104, due to a problem or abnormality occurred in the mountedlens apparatus: in this case, it is not possible to calculate acorrection amount for correcting a focus position by autofocusdetection.

In this embodiment, similarly to step S2102 in this embodiment, thesystem controller 1223 determines in step S2109 shown in FIG. 23 whethera lens apparatus is mounted on the electronic camera 1200 and whether acorrection amount calculation process by the AF calibration mode can beperformed on the mounted lens apparatus, based on lens informationobtained from the lens control circuit of the mounted lens apparatus. Atthe same time, the system controller 1223 determines that the selectivesetting of the AF calibration mode is impossible, depending on thesetting state of the lens apparatus mounted on the electronic camera1200, that is., in the cases where the above-described setting states(1) to (6) of the lens apparatus are detected.

The other processes are the same as those of Embodiment 7.

In Embodiments 7 and 8, the execution of the above-described correctionamount calculation mode is disabled in the cases where specific lensapparatuses are mounted or no lens apparatus is mounted. Here, examplesof the specific lens apparatuses include a lens apparatus for manualfocusing only, a lens apparatus capable of shift-driving and/ortilt-driving, a lens apparatus for macro only and a lens apparatusmanufactured by a manufacturer different from that of the image-takingapparatus.

The execution of the correction amount calculation mode is also disabledin the care where the lens apparatus are set to specific states. Here,the specific state includes a setting state of the lens apparatus inwhich an autofocus adjustment operation can be performed based on afocus position corrected with a correction amount, a setting state inwhich a manual focus mode is set for a lens apparatus that can beswitched between a manual focus mode and an autofocus mode, a state inwhich one or both of shift-driving and tilt-driving are set, a state inwhich a macro mode is set, and a state in which the image-taking lens isdriven outside a predetermined object distance range.

Accordingly, it is possible to ensure an accurate correction operationat the time of correcting variations in performance among individuallens apparatuses in the camera, and the user can easily determinewhether the camera can correct variations in performance amongindividual lens apparatuses.

It should be noted that an object of the present invention can also beachieved by supplying a recording medium in which a software programcode which realizes the functions of Embodiment 7 and 8 into a system oran apparatus, and letting a computer (or CPU, MPU or the like) of thesystem or the apparatus to read and execute the program code stored inthe recording medium.

In this case, the program code read from the recording medium realizesthe novel functions of the present invention, and the recording mediumstoring the program code and the program constitute the presentinvention.

Examples of the recording medium for supplying the program code includesflexible disks, hard disks, optical disks, magneto-optical disks,CD-ROMs, CD-Rs, CD-RWs, DVD-ROMs, DVD-RAMs, DVD+RWs, DVD+RWs, magnetictapes, nonvolatile memory cards and ROMs. Or, the above-describedprogram may be supplied by downloading from another computer, data base.or the like connected to the Internet, a commercial network, a localarea network or the like.

In addition to the case where the computer executes the read programcode and thereby realizes the functions of each of the above-describedembodiments, the present invention also includes the case where an OS(operating system) or the like operating on the computer performs aportion or all the actual processes in accordance with the direction ofthe program code and the functions of each of the above-describedembodiments are realized by that process.

Furthermore, the present invention includes the case where, after theprogram code read from the recording medium is written in a memory whichis provided in a function expansion board inserted in the computer or afunction expansion unit connected to the computer, a CPU or the likeprovided in the function expansion board or the function expansion unitperforms a portion of all the actual processes in accordance with thedirection of the program code and the functions of each of Embodiments 7and 8 described above are realized by that process.

While preferred embodiments have been described, it is to be understoodthat modification and variation of the present invention may be madewithout departing from the scope of the following claims. “thisapplication claims priorities from Japanese Patent Application Nos.2003-417349 filed Dec. 15, 2003, 2004-178451 filed Jun. 16, 2004 and2004-037645 filed Feb. 16, 2004 which are hereby incorporated byreference herein.”

1. A camera on which a lens apparatus is mounted, comprising: acontroller which performs a focusing control corresponding to themounted lens apparatus; a display unit which performs display processcorresponding to an output of the controller; and a storage sectionwhich stores correction information for correcting a calculation resultin the focusing control by the controller, in association with themounted lens apparatus; wherein the controller identifies the mountedlens apparatus, determines whether the correction informationcorresponding to the identified lens apparatus is stored in the storagesection, and outputs a signal corresponding to a result of thedetermination to the display unit.
 2. The camera according to claim 1,wherein the controller determines the correction information in a statein which the lens apparatus is mounted on the camera, and stores thedetermined correction information in the storage section in associationwith the lens apparatus.
 3. The camera according to claim 1, wherein, ina case where the correction information corresponding to the mountedlens apparatus is stored in the storage section, the controller displaysthe correction information on the display unit.
 4. The camera accordingto claim 1, further comprising: a detector which detects a mounted stateof the lens apparatus, wherein the controller performs the determinationin a case where the detector detects that the lens apparatus is mounted.5. The camera according to claim 1, further comprising: an operationunit which instructs the controller to perform the determination inaccordance with an operation by a user.
 6. The camera according to claim1, wherein the controller provides a warning with the display unit in acase where the correction information corresponding to the mounted lensapparatus is not stored in the storage section.
 7. A camera systemcomprising: a camera according to claim 1; and a lens apparatus mountedon the camera.
 8. A lens apparatus mounted on a camera comprising acontroller which performs a focusing control corresponding to themounted lens apparatus, the lens apparatus comprising: a lens; and astorage section which stores correction information for correcting acalculation result in the focusing control by the controller.
 9. Acamera system comprising: a lens apparatus; and a camera on which thelens apparatus is mounted; wherein the camera comprises a controllerwhich performs a focusing control corresponding to the mounted lensapparatus, and a display unit which performs display processcorresponding to an output of the controller, wherein the lens apparatuscomprises a storage section which stores correction information forcorrecting a calculation result in the focusing control by thecontroller, and wherein the controller identifies the mounted lensapparatus, determines whether the correction information correspondingto the identified lens apparatus is stored in the storage section, andoutputs a signal corresponding to a result of the determination to thedisplay unit.
 10. A method for controlling a camera on which a lensapparatus is mounted, the method comprising: a first step of performinga focusing control corresponding to the mounted lens apparatus; a secondstep of storing correction information for correcting a calculationresults in the focusing control, in association with the mounted lensapparatus; a third step of identifying the mounted lens apparatus; and aforth step of determining whether the correction informationcorresponding to the identified lens apparatus is stored and outputtinga signal corresponding to a result of the determination.
 11. A camera onwhich a plurality of lens apparatuses capable of focusing control can beselectively mounted, comprising: a focus detection section which obtainsfirst information used for the focusing control, using a light flux fromthe mounted lens apparatus; a storage section which stores secondinformation for correcting the first information; and a correctionsection which corrects the first information based on the secondinformation; wherein the second information is information associatedwith individual information assigned to each lens apparatus mounted onthe camera.
 12. The camera according to claim 11, wherein the individualinformation varies from one lens apparatus to another even in a casewhere the plurality of lens apparatuses are of the same type.
 13. Thecamera according to claim 11, wherein the individual informationincludes at least a serial number of the lens apparatus.
 14. A lensapparatus selectively mounted on a plurality of cameras comprising afocus detection section which obtains first information used forfocusing control, using a light flux from the lens apparatus mounted onthe camera, the lens apparatus comprising: a storage section whichstores second information for correcting the first information; and acorrection section which corrects the first information based on thesecond information; wherein the second information is informationassociated with individual information assigned to each camera on whichthe lens apparatus is mounted.
 15. The lens apparatus according to claim14, wherein the individual information varies from one camera to anothereven in a case where the plurality of cameras are of the same type. 16.The lens apparatus according to claim 14, wherein the individualinformation includes at least a serial number of the camera.
 17. Acamera on which a plurality of lens apparatuses are selectively mounted,comprising: an image-pickup element which photoelectrically converts anobject image formed by an image-taking optical system in the mountedlens apparatus; an image-taking process section which performs animage-taking process of an image, using the image-pickup element; adetection section which detects a defocus amount of the image-takingoptical system; a controller which sequentially changes the defocusamount and instructs the image-taking process section to perform theimage-taking process of a plurality of images which differ in thedefocus amount; a determination section which determines the defocusamount corresponding to a specific image included in the plurality ofimages; and a storage section which stores identification information ofthe lens apparatus in association with the defocus amount determinedwith the determination section, wherein the controller performs afocusing control in the image-taking optical system, using the defocusamount corresponding to the lens apparatus mounted on the camera,determines identification information of the lens apparatus mounted onthe camera, and controls the image-taking process for obtaining theplurality of images in accordance with a result of the determination.18. The camera according to claim 17, wherein the controller disablesthe image-taking process in a case where it determines that apredetermined lens apparatus is mounted based on the identificationinformation.
 19. The camera according to claim 17, further comprising: asetting section which performs setting of the image-taking process,wherein the controller provides a warning against setting of theimage-taking process by the setting section in a case where itdetermines that a predetermined lens apparatus is mounted based on theidentification information.
 20. The camera according to claim 18,wherein the predetermined lens apparatus is a lens apparatus for manualfocus only.
 21. The camera according to claim 18, wherein thepredetermined lens apparatus is a lens apparatus which lets a portion ofthe image-taking optical system perform at least one of shift-drivingand tilt-driving.
 22. The camera according to claim 18, wherein thepredetermined lens apparatus is a lens apparatus used for only a macroimage-taking.
 23. The camera according to claim 17, wherein thecontroller determines whether the lens apparatus is mounted on thecamera, and disables the image-taking process in a case where the lensapparatus is not mounted.
 24. A camera on which a plurality of lensapparatuses are selectively mounted, comprising: an image-pickup elementwhich photoelectrically converts an object image formed by animage-taking optical system in the mounted lens apparatus; animage-taking process section which performs an image-taking process ofan image, using the image-pickup element; a detection section whichdetects a defocus amount of the image-taking optical system; acontroller which sequentially changes the defocus amount and instructsthe image-taking process section to perform image-taking process of aplurality of images which differ in the defocus amount; a determinationsection which determines the defocus amount corresponding to a specificimage included in the plurality of images; and a storage section whichstores identification information of the lens apparatus in associationwith the defocus amount determined with the determination section,wherein the controller performs a focusing control in the image-takingoptical system, using the defocus amount corresponding to the lensapparatus mounted on the camera, determines a state of the lensapparatus mounted on the camera, and controls the image-taking processfor obtaining the plurality of images in accordance with a result of thedetermination.
 25. A method for controlling a camera on which aplurality of lens apparatuses are selectively mounted and whichcomprises an image-pickup element which photoelectrically converts anobject image, the method comprising: a first step of sequentiallychanging a defocus amount of an image-taking optical system which formsthe object image, and performing image-taking process of a plurality ofimages which differ in the defocus amount; a second step of determiningthe defocus amount corresponding to a specific image included in theplurality of images; a third step of storing identification informationof the lens apparatus in association with the defocus amount determinedin the second step; and a fourth step of performing a focusing controlin the image-taking optical system, using the defocus amountcorresponding to the lens apparatus mounted on the camera; wherein, inthe first step, identification information of the lens apparatus mountedon the camera is determined, and an image-taking process for obtainingthe plurality of images is controlled in accordance with a result of thedetermination.
 26. A method for controlling a camera on which aplurality of lens apparatuses are selectively mounted and whichcomprises an image-pickup element which photoelectrically converts anobject image, the method comprising: a first step of sequentiallychanging a defocus amount of an image-taking optical system which formsthe object image, and performing image-taking process of a plurality ofimages which differ in the defocus amount; a second step of determiningthe defocus amount corresponding to a specific image included in theplurality of images; a third step of storing identification informationof the lens apparatus in association with the defocus amount determinedin the second step; and a fourth step of performing a focusing controlin the image-taking optical system, using the defocus amountcorresponding to the lens apparatus mounted on the camera; wherein, inthe first step, a state of the lens apparatus mounted on the camera isdetermined, and an image-taking process for obtaining the plurality ofimages is controlled in accordance with a result of the determination.27. A program for letting a computer execute a method for controlling acamera on which a plurality of lens apparatuses are selectively mountedand which comprises an image-pickup element which photoelectricallyconverts an object image, the program comprising: a first step ofsequentially changing a defocus amount of an image-taking optical systemwhich forms the object image, and performing image-taking process of aplurality of images which differ in the defocus amount; a second step ofdetermining the defocus amount corresponding to a specific imageincluded in the plurality of images; a third step of storingidentification information of the lens apparatus in association with thedefocus amount determined in the second step; and a fourth step ofperforming a focusing control in the image-taking optical system, usingthe defocus amount corresponding to the lens apparatus mounted on thecamera; wherein, in the first step, identification information of thelens apparatus mounted on the camera is determined, and an image-takingprocess for obtaining the plurality of images is controlled inaccordance with a result of the determination.
 28. A program for lettinga computer execute a method for controlling a camera on which aplurality of lens apparatuses are selectively mounted and whichcomprises an image-pickup element which photoelectrically converts anobject image, the program comprising: a first step of sequentiallychanging a defocus amount of an image-taking optical system which formsthe object image, and performing image-taking process of a plurality ofimages which differ in the defocus amount; a second step of determiningthe defocus amount corresponding to a specific image included in theplurality of images; a third step of storing identification informationof the lens apparatus in association with the defocus amount determinedin the second step; and a fourth step of performing a focusing controlin the image-taking optical system, using the defocus amountcorresponding to the lens apparatus mounted on the camera; wherein, inthe first step, a state of the lens apparatus mounted on the camera isdetermined, and an image-taking process for obtaining the plurality ofimages is controlled in accordance with a result of the determination.